diff --git a/CHANGELOG.md b/CHANGELOG.md
index f8baacc01e..8f178b7c02 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,8 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 
 ### Added
 
+- Implementation of the Excel `AVERAGEIFS()` functions as part of a restructuring of Database functions and Conditional Statistical functions.
 - Support for date values and percentages in query parameters for Database functions, and the IF expressions in functions like COUNTIF() and AVERAGEIF(). [#1875](https://github.com/PHPOffice/PhpSpreadsheet/pull/1875)
-- Support for booleans, and for wildcard text search in query parameters for Database functions. [#1876](https://github.com/PHPOffice/PhpSpreadsheet/pull/1876)
+- Support for booleans, and for wildcard text search in query parameters for Database functions, and the IF expressions in functions like COUNTIF() and AVERAGEIF(). [#1876](https://github.com/PHPOffice/PhpSpreadsheet/pull/1876)
 - Implemented DataBar for conditional formatting in Xlsx, providing read/write and creation of (type, value, direction, fills, border, axis position, color settings) as DataBar options in Excel. [#1754](https://github.com/PHPOffice/PhpSpreadsheet/pull/1754)
 - Alignment for ODS Writer [#1796](https://github.com/PHPOffice/PhpSpreadsheet/issues/1796)
 - Basic implementation of the PERMUTATIONA() Statistical Function
diff --git a/src/PhpSpreadsheet/Calculation/Calculation.php b/src/PhpSpreadsheet/Calculation/Calculation.php
index ba6299572f..e114a00d19 100644
--- a/src/PhpSpreadsheet/Calculation/Calculation.php
+++ b/src/PhpSpreadsheet/Calculation/Calculation.php
@@ -343,12 +343,12 @@ class Calculation
         ],
         'AVERAGEIF' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'AVERAGEIF'],
+            'functionCall' => [Statistical\Conditional::class, 'AVERAGEIF'],
             'argumentCount' => '2,3',
         ],
         'AVERAGEIFS' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Functions::class, 'DUMMY'],
+            'functionCall' => [Statistical\Conditional::class, 'AVERAGEIFS'],
             'argumentCount' => '3+',
         ],
         'BAHTTEXT' => [
@@ -639,12 +639,12 @@ class Calculation
         ],
         'COUNTIF' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'COUNTIF'],
+            'functionCall' => [Statistical\Conditional::class, 'COUNTIF'],
             'argumentCount' => '2',
         ],
         'COUNTIFS' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'COUNTIFS'],
+            'functionCall' => [Statistical\Conditional::class, 'COUNTIFS'],
             'argumentCount' => '2+',
         ],
         'COUPDAYBS' => [
@@ -1630,7 +1630,7 @@ class Calculation
         ],
         'MAXIFS' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'MAXIFS'],
+            'functionCall' => [Statistical\Conditional::class, 'MAXIFS'],
             'argumentCount' => '3+',
         ],
         'MDETERM' => [
@@ -1675,7 +1675,7 @@ class Calculation
         ],
         'MINIFS' => [
             'category' => Category::CATEGORY_STATISTICAL,
-            'functionCall' => [Statistical::class, 'MINIFS'],
+            'functionCall' => [Statistical\Conditional::class, 'MINIFS'],
             'argumentCount' => '3+',
         ],
         'MINUTE' => [
diff --git a/src/PhpSpreadsheet/Calculation/Database.php b/src/PhpSpreadsheet/Calculation/Database.php
index db16e2df8f..7643197988 100644
--- a/src/PhpSpreadsheet/Calculation/Database.php
+++ b/src/PhpSpreadsheet/Calculation/Database.php
@@ -34,7 +34,7 @@ class Database
      *                                        the column label in which you specify a condition for the
      *                                        column.
      *
-     * @return float|string
+     * @return null|float|string
      */
     public static function DAVERAGE($database, $field, $criteria)
     {
diff --git a/src/PhpSpreadsheet/Calculation/Database/DAverage.php b/src/PhpSpreadsheet/Calculation/Database/DAverage.php
index 899b242669..ea45beda8f 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DAverage.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DAverage.php
@@ -29,7 +29,7 @@ class DAverage extends DatabaseAbstract
      *                              the column label in which you specify a condition for the
      *                              column.
      *
-     * @return float|string
+     * @return null|float|string
      */
     public static function evaluate($database, $field, $criteria)
     {
diff --git a/src/PhpSpreadsheet/Calculation/Database/DCountA.php b/src/PhpSpreadsheet/Calculation/Database/DCountA.php
index 5e2ef110f0..1beaf012d9 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DCountA.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DCountA.php
@@ -36,7 +36,7 @@ public static function evaluate($database, $field, $criteria)
         $field = self::fieldExtract($database, $field);
 
         return Statistical::COUNTA(
-            self::getFilteredColumn($database, $field, $criteria)
+            self::getFilteredColumn($database, $field ?? 0, $criteria)
         );
     }
 }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DGet.php b/src/PhpSpreadsheet/Calculation/Database/DGet.php
index 64858d9d28..c2ffe30265 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DGet.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DGet.php
@@ -44,6 +44,8 @@ public static function evaluate($database, $field, $criteria)
             return Functions::NAN();
         }
 
-        return $columnData[0];
+        $row = array_pop($columnData);
+
+        return array_pop($row);
     }
 }
diff --git a/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php b/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php
index a08f1251fc..2148ebc0b9 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php
@@ -25,19 +25,20 @@ abstract public static function evaluate($database, $field, $criteria);
      *                                        represents the position of the column within the list: 1 for
      *                                        the first column, 2 for the second column, and so on.
      */
-    protected static function fieldExtract(array $database, $field): ?string
+    protected static function fieldExtract(array $database, $field): ?int
     {
         $field = strtoupper(Functions::flattenSingleValue($field));
-        $fieldNames = array_map('strtoupper', array_shift($database));
+        if ($field === '') {
+            return null;
+        }
 
+        $fieldNames = array_map('strtoupper', array_shift($database));
         if (is_numeric($field)) {
-            $keys = array_keys($fieldNames);
-
-            return $keys[$field - 1];
+            return ((int) $field) - 1;
         }
-        $key = array_search($field, $fieldNames);
+        $key = array_search($field, array_values($fieldNames), true);
 
-        return $key ?: null;
+        return ($key !== false) ? (int) $key : null;
     }
 
     /**
@@ -70,14 +71,19 @@ protected static function filter(array $database, array $criteria): array
         return self::executeQuery($database, $query, $criteriaNames, $fieldNames);
     }
 
-    protected static function getFilteredColumn(array $database, $field, array $criteria): array
+    protected static function getFilteredColumn(array $database, ?int $field, array $criteria): array
     {
         //    reduce the database to a set of rows that match all the criteria
         $database = self::filter($database, $criteria);
+        $defaultReturnColumnValue = ($field === null) ? 1 : null;
+
         //    extract an array of values for the requested column
         $columnData = [];
-        foreach ($database as $row) {
-            $columnData[] = ($field !== null) ? $row[$field] : true;
+        foreach ($database as $rowKey => $row) {
+            $keys = array_keys($row);
+            $key = $keys[$field] ?? null;
+            $columnKey = $key ?? 'A';
+            $columnData[$rowKey][$columnKey] = $row[$key] ?? $defaultReturnColumnValue;
         }
 
         return $columnData;
diff --git a/src/PhpSpreadsheet/Calculation/Internal/WildcardMatch.php b/src/PhpSpreadsheet/Calculation/Internal/WildcardMatch.php
index 5b4fe5b14d..2ba2034686 100644
--- a/src/PhpSpreadsheet/Calculation/Internal/WildcardMatch.php
+++ b/src/PhpSpreadsheet/Calculation/Internal/WildcardMatch.php
@@ -5,9 +5,9 @@
 class WildcardMatch
 {
     private const SEARCH_SET = [
-        '/([^~])(\*)/ui',
+        '/(?<!~)\*/ui',
         '/~\*/ui',
-        '/([^~])(\?)/ui',
+        '/(?<!~)\?/ui',
         '/~\?/ui',
     ];
 
@@ -20,6 +20,11 @@ class WildcardMatch
 
     public static function wildcard(string $wildcard): string
     {
+        // Preg Escape the wildcard, but protecting the Excel * and ? search characters
+        $wildcard = str_replace(['*', '?'], [0x1A, 0x1B], $wildcard);
+        $wildcard = preg_quote($wildcard);
+        $wildcard = str_replace([0x1A, 0x1B], ['*', '?'], $wildcard);
+
         return preg_replace(self::SEARCH_SET, self::REPLACEMENT_SET, $wildcard);
     }
 
@@ -29,6 +34,6 @@ public static function compare($value, string $wildcard): bool
             return true;
         }
 
-        return (bool) preg_match("/{$wildcard}/ui", $value);
+        return (bool) preg_match("/^{$wildcard}\$/mui", $value);
     }
 }
diff --git a/src/PhpSpreadsheet/Calculation/MathTrig.php b/src/PhpSpreadsheet/Calculation/MathTrig.php
index e62e949765..f12cc9df5a 100644
--- a/src/PhpSpreadsheet/Calculation/MathTrig.php
+++ b/src/PhpSpreadsheet/Calculation/MathTrig.php
@@ -1281,7 +1281,7 @@ public static function SUM(...$args)
     /**
      * SUMIF.
      *
-     * Counts the number of cells that contain numbers within the list of arguments
+     * Totals the values of cells that contain numbers within the list of arguments
      *
      * Excel Function:
      *        SUMIF(value1[,value2[, ...]],condition)
@@ -1327,7 +1327,7 @@ public static function SUMIF($aArgs, $condition, $sumArgs = [])
     /**
      * SUMIFS.
      *
-     *    Counts the number of cells that contain numbers within the list of arguments
+     *    Totals the values of cells that contain numbers within the list of arguments
      *
      *    Excel Function:
      *        SUMIFS(value1[,value2[, ...]],condition)
diff --git a/src/PhpSpreadsheet/Calculation/Statistical.php b/src/PhpSpreadsheet/Calculation/Statistical.php
index f7d0c05ff7..2f695d5b3d 100644
--- a/src/PhpSpreadsheet/Calculation/Statistical.php
+++ b/src/PhpSpreadsheet/Calculation/Statistical.php
@@ -2,6 +2,7 @@
 
 namespace PhpOffice\PhpSpreadsheet\Calculation;
 
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Conditional;
 use PhpOffice\PhpSpreadsheet\Calculation\Statistical\Permutations;
 use PhpOffice\PhpSpreadsheet\Shared\Trend\Trend;
 
@@ -701,47 +702,20 @@ public static function AVERAGEA(...$args)
      * Excel Function:
      *        AVERAGEIF(value1[,value2[, ...]],condition)
      *
-     * @param mixed $aArgs Data values
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Conditional::AVERAGEIF()
+     *      Use the AVERAGEIF() method in the Statistical\Conditional class instead
+     *
+     * @param mixed $range Data values
      * @param string $condition the criteria that defines which cells will be checked
-     * @param mixed[] $averageArgs Data values
+     * @param mixed[] $averageRange Data values
      *
-     * @return float|string
+     * @return null|float|string
      */
-    public static function AVERAGEIF($aArgs, $condition, $averageArgs = [])
+    public static function AVERAGEIF($range, $condition, $averageRange = [])
     {
-        $returnValue = 0;
-
-        $aArgs = Functions::flattenArray($aArgs);
-        $averageArgs = Functions::flattenArray($averageArgs);
-        if (empty($averageArgs)) {
-            $averageArgs = $aArgs;
-        }
-        $condition = Functions::ifCondition($condition);
-        $conditionIsNumeric = strpos($condition, '"') === false;
-
-        // Loop through arguments
-        $aCount = 0;
-        foreach ($aArgs as $key => $arg) {
-            if (!is_numeric($arg)) {
-                if ($conditionIsNumeric) {
-                    continue;
-                }
-                $arg = Calculation::wrapResult(strtoupper($arg));
-            } elseif (!$conditionIsNumeric) {
-                continue;
-            }
-            $testCondition = '=' . $arg . $condition;
-            if (Calculation::getInstance()->_calculateFormulaValue($testCondition)) {
-                $returnValue += $averageArgs[$key];
-                ++$aCount;
-            }
-        }
-
-        if ($aCount > 0) {
-            return $returnValue / $aCount;
-        }
-
-        return Functions::DIV0();
+        return Statistical\Conditional::AVERAGEIF($range, $condition, $averageRange);
     }
 
     /**
@@ -1137,38 +1111,21 @@ public static function COUNTBLANK(...$args)
      * Counts the number of cells that contain numbers within the list of arguments
      *
      * Excel Function:
-     *        COUNTIF(value1[,value2[, ...]],condition)
+     *        COUNTIF(range,condition)
      *
-     * @param mixed $aArgs Data values
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Conditional::COUNTIF()
+     *      Use the COUNTIF() method in the Statistical\Conditional class instead
+     *
+     * @param mixed $range Data values
      * @param string $condition the criteria that defines which cells will be counted
      *
      * @return int
      */
-    public static function COUNTIF($aArgs, $condition)
+    public static function COUNTIF($range, $condition)
     {
-        $returnValue = 0;
-
-        $aArgs = Functions::flattenArray($aArgs);
-        $condition = Functions::ifCondition($condition);
-        $conditionIsNumeric = strpos($condition, '"') === false;
-        // Loop through arguments
-        foreach ($aArgs as $arg) {
-            if (!is_numeric($arg)) {
-                if ($conditionIsNumeric) {
-                    continue;
-                }
-                $arg = Calculation::wrapResult(strtoupper($arg));
-            } elseif (!$conditionIsNumeric) {
-                continue;
-            }
-            $testCondition = '=' . $arg . $condition;
-            if (Calculation::getInstance()->_calculateFormulaValue($testCondition)) {
-                // Is it a value within our criteria
-                ++$returnValue;
-            }
-        }
-
-        return $returnValue;
+        return Statistical\Conditional::COUNTIF($range, $condition);
     }
 
     /**
@@ -1179,66 +1136,18 @@ public static function COUNTIF($aArgs, $condition)
      * Excel Function:
      *        COUNTIFS(criteria_range1, criteria1, [criteria_range2, criteria2]…)
      *
-     * @param mixed $args Criterias
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Conditional::COUNTIFS()
+     *      Use the COUNTIFS() method in the Statistical\Conditional class instead
+     *
+     * @param mixed $args Pairs of Ranges and Criteria
      *
      * @return int
      */
     public static function COUNTIFS(...$args)
     {
-        $arrayList = $args;
-
-        // Return value
-        $returnValue = 0;
-
-        if (empty($arrayList)) {
-            return $returnValue;
-        }
-
-        $aArgsArray = [];
-        $conditions = [];
-
-        while (count($arrayList) > 0) {
-            $aArgsArray[] = Functions::flattenArray(array_shift($arrayList));
-            $conditions[] = Functions::ifCondition(array_shift($arrayList));
-        }
-
-        // Loop through each arg and see if arguments and conditions are true
-        foreach (array_keys($aArgsArray[0]) as $index) {
-            $valid = true;
-
-            foreach ($conditions as $cidx => $condition) {
-                $conditionIsNumeric = strpos($condition, '"') === false;
-                $arg = $aArgsArray[$cidx][$index];
-
-                // Loop through arguments
-                if (!is_numeric($arg)) {
-                    if ($conditionIsNumeric) {
-                        $valid = false;
-
-                        break; // if false found, don't need to check other conditions
-                    }
-                    $arg = Calculation::wrapResult(strtoupper($arg));
-                } elseif (!$conditionIsNumeric) {
-                    $valid = false;
-
-                    break; // if false found, don't need to check other conditions
-                }
-                $testCondition = '=' . $arg . $condition;
-                if (!Calculation::getInstance()->_calculateFormulaValue($testCondition)) {
-                    // Is not a value within our criteria
-                    $valid = false;
-
-                    break; // if false found, don't need to check other conditions
-                }
-            }
-
-            if ($valid) {
-                ++$returnValue;
-            }
-        }
-
-        // Return
-        return $returnValue;
+        return Statistical\Conditional::COUNTIFS(...$args);
     }
 
     /**
@@ -2348,53 +2257,18 @@ public static function MAXA(...$args)
      * Excel Function:
      *        MAXIFS(max_range, criteria_range1, criteria1, [criteria_range2, criteria2], ...)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Conditional::MAXIFS()
+     *      Use the MAXIFS() method in the Statistical\Conditional class instead
+     *
      * @param mixed $args Data range and criterias
      *
      * @return float
      */
     public static function MAXIFS(...$args)
     {
-        $arrayList = $args;
-
-        // Return value
-        $returnValue = null;
-
-        $maxArgs = Functions::flattenArray(array_shift($arrayList));
-        $aArgsArray = [];
-        $conditions = [];
-
-        while (count($arrayList) > 0) {
-            $aArgsArray[] = Functions::flattenArray(array_shift($arrayList));
-            $conditions[] = Functions::ifCondition(array_shift($arrayList));
-        }
-
-        // Loop through each arg and see if arguments and conditions are true
-        foreach ($maxArgs as $index => $value) {
-            $valid = true;
-
-            foreach ($conditions as $cidx => $condition) {
-                $arg = $aArgsArray[$cidx][$index];
-
-                // Loop through arguments
-                if (!is_numeric($arg)) {
-                    $arg = Calculation::wrapResult(strtoupper($arg));
-                }
-                $testCondition = '=' . $arg . $condition;
-                if (!Calculation::getInstance()->_calculateFormulaValue($testCondition)) {
-                    // Is not a value within our criteria
-                    $valid = false;
-
-                    break; // if false found, don't need to check other conditions
-                }
-            }
-
-            if ($valid) {
-                $returnValue = $returnValue === null ? $value : max($value, $returnValue);
-            }
-        }
-
-        // Return
-        return $returnValue;
+        return Conditional::MAXIFS(...$args);
     }
 
     /**
@@ -2520,53 +2394,18 @@ public static function MINA(...$args)
      * Excel Function:
      *        MINIFS(min_range, criteria_range1, criteria1, [criteria_range2, criteria2], ...)
      *
+     * @Deprecated 1.17.0
+     *
+     * @see Statistical\Conditional::MINIFS()
+     *      Use the MINIFS() method in the Statistical\Conditional class instead
+     *
      * @param mixed $args Data range and criterias
      *
      * @return float
      */
     public static function MINIFS(...$args)
     {
-        $arrayList = $args;
-
-        // Return value
-        $returnValue = null;
-
-        $minArgs = Functions::flattenArray(array_shift($arrayList));
-        $aArgsArray = [];
-        $conditions = [];
-
-        while (count($arrayList) > 0) {
-            $aArgsArray[] = Functions::flattenArray(array_shift($arrayList));
-            $conditions[] = Functions::ifCondition(array_shift($arrayList));
-        }
-
-        // Loop through each arg and see if arguments and conditions are true
-        foreach ($minArgs as $index => $value) {
-            $valid = true;
-
-            foreach ($conditions as $cidx => $condition) {
-                $arg = $aArgsArray[$cidx][$index];
-
-                // Loop through arguments
-                if (!is_numeric($arg)) {
-                    $arg = Calculation::wrapResult(strtoupper($arg));
-                }
-                $testCondition = '=' . $arg . $condition;
-                if (!Calculation::getInstance()->_calculateFormulaValue($testCondition)) {
-                    // Is not a value within our criteria
-                    $valid = false;
-
-                    break; // if false found, don't need to check other conditions
-                }
-            }
-
-            if ($valid) {
-                $returnValue = $returnValue === null ? $value : min($value, $returnValue);
-            }
-        }
-
-        // Return
-        return $returnValue;
+        return Conditional::MINIFS(...$args);
     }
 
     //
diff --git a/src/PhpSpreadsheet/Calculation/Statistical/Conditional.php b/src/PhpSpreadsheet/Calculation/Statistical/Conditional.php
new file mode 100644
index 0000000000..02bb0782f3
--- /dev/null
+++ b/src/PhpSpreadsheet/Calculation/Statistical/Conditional.php
@@ -0,0 +1,234 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Database\DAverage;
+use PhpOffice\PhpSpreadsheet\Calculation\Database\DCount;
+use PhpOffice\PhpSpreadsheet\Calculation\Database\DMax;
+use PhpOffice\PhpSpreadsheet\Calculation\Database\DMin;
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+
+class Conditional
+{
+    private const CONDITION_COLUMN_NAME = 'CONDITION';
+    private const VALUE_COLUMN_NAME = 'VALUE';
+    private const CONDITIONAL_COLUMN_NAME = 'CONDITIONAL %d';
+
+    /**
+     * AVERAGEIF.
+     *
+     * Returns the average value from a range of cells that contain numbers within the list of arguments
+     *
+     * Excel Function:
+     *        AVERAGEIF(range,condition[, average_range])
+     *
+     * @param mixed[] $range Data values
+     * @param string $condition the criteria that defines which cells will be checked
+     * @param mixed[] $averageRange Data values
+     *
+     * @return null|float|string
+     */
+    public static function AVERAGEIF($range, $condition, $averageRange = [])
+    {
+        $range = Functions::flattenArray($range);
+        $averageRange = Functions::flattenArray($averageRange);
+        if (empty($averageRange)) {
+            $averageRange = $range;
+        }
+
+        $database = array_map(
+            null,
+            array_merge([self::CONDITION_COLUMN_NAME], $range),
+            array_merge([self::VALUE_COLUMN_NAME], $averageRange)
+        );
+
+        $condition = [[self::CONDITION_COLUMN_NAME, self::VALUE_COLUMN_NAME], [$condition, null]];
+
+        return DAverage::evaluate($database, self::VALUE_COLUMN_NAME, $condition);
+    }
+
+    /**
+     * AVERAGEIFS.
+     *
+     * Counts the number of cells that contain numbers within the list of arguments
+     *
+     * Excel Function:
+     *        AVERAGEIFS(average_range, criteria_range1, criteria1, [criteria_range2, criteria2]…)
+     *
+     * @param mixed $args Pairs of Ranges and Criteria
+     *
+     * @return null|float|string
+     */
+    public static function AVERAGEIFS(...$args)
+    {
+        if (empty($args)) {
+            return 0.0;
+        } elseif (count($args) === 3) {
+            return self::AVERAGEIF($args[2], $args[1], $args[0]);
+        }
+
+        $conditions = self::buildConditionSet(...$args);
+        $database = self::buildDatabase(...$args);
+
+        return DAverage::evaluate($database, self::VALUE_COLUMN_NAME, $conditions);
+    }
+
+    /**
+     * COUNTIF.
+     *
+     * Counts the number of cells that contain numbers within the list of arguments
+     *
+     * Excel Function:
+     *        COUNTIF(range,condition)
+     *
+     * @param mixed[] $range Data values
+     * @param string $condition the criteria that defines which cells will be counted
+     *
+     * @return int
+     */
+    public static function COUNTIF($range, $condition)
+    {
+        // Filter out any empty values that shouldn't be included in a COUNT
+        $range = array_filter(
+            Functions::flattenArray($range),
+            function ($value) {
+                return $value !== null && $value !== '';
+            }
+        );
+
+        $range = array_merge([[self::CONDITION_COLUMN_NAME]], array_chunk($range, 1));
+        $condition = array_merge([[self::CONDITION_COLUMN_NAME]], [[$condition]]);
+
+        return DCount::evaluate($range, null, $condition);
+    }
+
+    /**
+     * COUNTIFS.
+     *
+     * Counts the number of cells that contain numbers within the list of arguments
+     *
+     * Excel Function:
+     *        COUNTIFS(criteria_range1, criteria1, [criteria_range2, criteria2]…)
+     *
+     * @param mixed $args Pairs of Ranges and Criteria
+     *
+     * @return int
+     */
+    public static function COUNTIFS(...$args)
+    {
+        if (empty($args)) {
+            return 0;
+        } elseif (count($args) === 2) {
+            return self::COUNTIF(...$args);
+        }
+
+        $conditions = $database = [];
+        $pairCount = 1;
+        while (count($args) > 0) {
+            $conditions[] = array_merge([sprintf(self::CONDITIONAL_COLUMN_NAME, $pairCount)], [array_pop($args)]);
+            $database[] = array_merge(
+                [sprintf(self::CONDITIONAL_COLUMN_NAME, $pairCount)],
+                Functions::flattenArray(array_pop($args))
+            );
+            ++$pairCount;
+        }
+
+        $conditions = array_map(null, ...$conditions);
+        $database = array_map(null, ...$database);
+
+        return DCount::evaluate($database, null, $conditions);
+    }
+
+    /**
+     * MAXIFS.
+     *
+     * Returns the maximum value within a range of cells that contain numbers within the list of arguments
+     *
+     * Excel Function:
+     *        MAXIFS(max_range, criteria_range1, criteria1, [criteria_range2, criteria2]…)
+     *
+     * @param mixed $args Pairs of Ranges and Criteria
+     *
+     * @return null|float|string
+     */
+    public static function MAXIFS(...$args)
+    {
+        if (empty($args)) {
+            return 0.0;
+        }
+
+        $conditions = self::buildConditionSet(...$args);
+        $database = self::buildDatabase(...$args);
+
+        return DMax::evaluate($database, self::VALUE_COLUMN_NAME, $conditions);
+    }
+
+    /**
+     * MINIFS.
+     *
+     * Returns the minimum value within a range of cells that contain numbers within the list of arguments
+     *
+     * Excel Function:
+     *        MINIFS(min_range, criteria_range1, criteria1, [criteria_range2, criteria2]…)
+     *
+     * @param mixed $args Pairs of Ranges and Criteria
+     *
+     * @return null|float|string
+     */
+    public static function MINIFS(...$args)
+    {
+        if (empty($args)) {
+            return 0.0;
+        }
+
+        $conditions = self::buildConditionSet(...$args);
+        $database = self::buildDatabase(...$args);
+
+        return DMin::evaluate($database, self::VALUE_COLUMN_NAME, $conditions);
+    }
+
+    private static function buildConditionSet(...$args): array
+    {
+        array_shift($args);
+
+        $conditions = [];
+        $pairCount = 1;
+        while (count($args) > 0) {
+            $conditions[] = array_merge([sprintf(self::CONDITIONAL_COLUMN_NAME, $pairCount)], [array_pop($args)]);
+            array_pop($args);
+            ++$pairCount;
+        }
+
+        if (count($conditions) === 1) {
+            return array_map(
+                function ($value) {
+                    return [$value];
+                },
+                $conditions[0]
+            );
+        }
+
+        return array_map(null, ...$conditions);
+    }
+
+    private static function buildDatabase(...$args): array
+    {
+        $database = [];
+        $database[] = array_merge(
+            [self::VALUE_COLUMN_NAME],
+            Functions::flattenArray(array_shift($args))
+        );
+
+        $pairCount = 1;
+        while (count($args) > 0) {
+            array_pop($args);
+            $database[] = array_merge(
+                [sprintf(self::CONDITIONAL_COLUMN_NAME, $pairCount)],
+                Functions::flattenArray(array_pop($args))
+            );
+            ++$pairCount;
+        }
+
+        return array_map(null, ...$database);
+    }
+}
diff --git a/src/PhpSpreadsheet/Worksheet/Worksheet.php b/src/PhpSpreadsheet/Worksheet/Worksheet.php
index 02305b7a7f..191199704d 100644
--- a/src/PhpSpreadsheet/Worksheet/Worksheet.php
+++ b/src/PhpSpreadsheet/Worksheet/Worksheet.php
@@ -824,7 +824,7 @@ public function getTitle()
     /**
      * Set title.
      *
-     * @param string $pValue String containing the dimension of this worksheet
+     * @param string $title String containing the dimension of this worksheet
      * @param bool $updateFormulaCellReferences Flag indicating whether cell references in formulae should
      *            be updated to reflect the new sheet name.
      *          This should be left as the default true, unless you are
@@ -835,10 +835,10 @@ public function getTitle()
      *
      * @return $this
      */
-    public function setTitle($pValue, $updateFormulaCellReferences = true, $validate = true)
+    public function setTitle($title, $updateFormulaCellReferences = true, $validate = true)
     {
         // Is this a 'rename' or not?
-        if ($this->getTitle() == $pValue) {
+        if ($this->getTitle() == $title) {
             return $this;
         }
 
@@ -847,37 +847,37 @@ public function setTitle($pValue, $updateFormulaCellReferences = true, $validate
 
         if ($validate) {
             // Syntax check
-            self::checkSheetTitle($pValue);
+            self::checkSheetTitle($title);
 
             if ($this->parent) {
                 // Is there already such sheet name?
-                if ($this->parent->sheetNameExists($pValue)) {
+                if ($this->parent->sheetNameExists($title)) {
                     // Use name, but append with lowest possible integer
 
-                    if (Shared\StringHelper::countCharacters($pValue) > 29) {
-                        $pValue = Shared\StringHelper::substring($pValue, 0, 29);
+                    if (Shared\StringHelper::countCharacters($title) > 29) {
+                        $title = Shared\StringHelper::substring($title, 0, 29);
                     }
                     $i = 1;
-                    while ($this->parent->sheetNameExists($pValue . ' ' . $i)) {
+                    while ($this->parent->sheetNameExists($title . ' ' . $i)) {
                         ++$i;
                         if ($i == 10) {
-                            if (Shared\StringHelper::countCharacters($pValue) > 28) {
-                                $pValue = Shared\StringHelper::substring($pValue, 0, 28);
+                            if (Shared\StringHelper::countCharacters($title) > 28) {
+                                $title = Shared\StringHelper::substring($title, 0, 28);
                             }
                         } elseif ($i == 100) {
-                            if (Shared\StringHelper::countCharacters($pValue) > 27) {
-                                $pValue = Shared\StringHelper::substring($pValue, 0, 27);
+                            if (Shared\StringHelper::countCharacters($title) > 27) {
+                                $title = Shared\StringHelper::substring($title, 0, 27);
                             }
                         }
                     }
 
-                    $pValue .= " $i";
+                    $title .= " $i";
                 }
             }
         }
 
         // Set title
-        $this->title = $pValue;
+        $this->title = $title;
         $this->dirty = true;
 
         if ($this->parent && $this->parent->getCalculationEngine()) {
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DCountATest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DCountATest.php
index 4cfea42f75..f5214ed0aa 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DCountATest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DCountATest.php
@@ -80,10 +80,6 @@ public function providerDCountA()
                     ['Science', 'Male'],
                 ],
             ],
-            /*
-             * Null value in datacolumn behaviour for DCOUNTA... will include not include a null value in the count
-             *      if it is an actual cell value; but it will be included if it is a literal... this test case is
-             *      currently passing literals
             [
                 1,
                 $this->database2(),
@@ -93,7 +89,6 @@ public function providerDCountA()
                     ['Math', 'Female'],
                 ],
             ],
-             */
             [
                 3,
                 $this->database2(),
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DSumTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DSumTest.php
index 10915b3c93..5c270fd2b1 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DSumTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Database/DSumTest.php
@@ -103,6 +103,15 @@ public function providerDSum()
                     ['3', 'C*'],
                 ],
             ],
+            [
+                705000,
+                $this->database2(),
+                'Sales',
+                [
+                    ['Quarter', 'Sales Rep.'],
+                    ['3', '<>C*'],
+                ],
+            ],
             [
                 null,
                 $this->database1(),
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/AverageIfsTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/AverageIfsTest.php
new file mode 100644
index 0000000000..84c53431c6
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/AverageIfsTest.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Calculation\Functions;
+use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+use PHPUnit\Framework\TestCase;
+
+class AverageIfsTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Functions::setCompatibilityMode(Functions::COMPATIBILITY_EXCEL);
+    }
+
+    /**
+     * @dataProvider providerAVERAGEIFS
+     *
+     * @param mixed $expectedResult
+     */
+    public function testAVERAGEIFS($expectedResult, ...$args): void
+    {
+        $result = Statistical\Conditional::AVERAGEIFS(...$args);
+        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
+    }
+
+    public function providerAVERAGEIFS()
+    {
+        return require 'tests/data/Calculation/Statistical/AVERAGEIFS.php';
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Helper/SampleTest.php b/tests/PhpSpreadsheetTests/Helper/SampleTest.php
index 8fd6bb47cb..cd87eda2c6 100644
--- a/tests/PhpSpreadsheetTests/Helper/SampleTest.php
+++ b/tests/PhpSpreadsheetTests/Helper/SampleTest.php
@@ -57,6 +57,9 @@ public function providerSample()
         $result = [];
         foreach ($helper->getSamples() as $samples) {
             foreach ($samples as $sample) {
+//                if (array_pop(explode('/', $sample)) !== 'DGET.php') {
+//                    continue;
+//                }
                 if (!in_array($sample, $skipped)) {
                     $file = 'samples/' . $sample;
                     $result[] = [$file];
diff --git a/tests/data/Calculation/Statistical/AVERAGEIF.php b/tests/data/Calculation/Statistical/AVERAGEIF.php
index 422a277130..736b833fab 100644
--- a/tests/data/Calculation/Statistical/AVERAGEIF.php
+++ b/tests/data/Calculation/Statistical/AVERAGEIF.php
@@ -46,8 +46,39 @@
         '<2013',
     ],
     [
-        14000,
-        [7000, 14000, 'Hello World', 21000, 28000],
+        200,
+        [7000, 14000, 21000, 28000],
         '<23000',
+        [100, 200, 300, 800],
+    ],
+    [
+        (2 + 4 + 8) / 3,
+        [true, true, false, true, false],
+        true,
+        [2, 4, 6, 8, 10],
+    ],
+    [
+        (6 + 10) / 2,
+        [true, true, false, true, false],
+        '<>true',
+        [2, 4, 6, 8, 10],
+    ],
+    [
+        (1 + 2 + 5 + 6) / 4,
+        ['North', 'South', 'East', 'West', 'North', 'South', 'East', 'West'],
+        '???th',
+        [1, 2, 3, 4, 5, 6, 7, 8],
+    ],
+    [
+        16733.5,
+        ['East', 'West', 'North', 'South (New Office)', 'Midwest'],
+        '=*West',
+        [45678, 23789, -4789, 0, 9678],
+    ],
+    [
+        18589,
+        ['East', 'West', 'North', 'South (New Office)', 'Midwest'],
+        '<>*(New Office)',
+        [45678, 23789, -4789, 0, 9678],
     ],
 ];
diff --git a/tests/data/Calculation/Statistical/AVERAGEIFS.php b/tests/data/Calculation/Statistical/AVERAGEIFS.php
new file mode 100644
index 0000000000..6c94300cc1
--- /dev/null
+++ b/tests/data/Calculation/Statistical/AVERAGEIFS.php
@@ -0,0 +1,42 @@
+<?php
+
+return [
+    [
+        80.5,
+        [75, 94, 86, 'incomplete'],
+        [75, 94, 86, 'incomplete'],
+        '>70',
+        [75, 94, 86, 'incomplete'],
+        '<90',
+    ],
+    [
+        '#DIV/0!',
+        [85, 80, 93, 75],
+        [85, 80, 93, 75],
+        '>95',
+    ],
+    [
+        87.5,
+        [87, 88, 'incomplete', 75],
+        [87, 88, 'incomplete', 75],
+        '<>incomplete',
+        [87, 88, 'incomplete', 75],
+        '>80',
+    ],
+    [
+        174000,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        1,
+        ['North', 'North', 'South', 'North', 'North', 'South', 'North', 'North', 'South', 'North', 'North', 'South'],
+        'North',
+    ],
+    [
+        285500,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        '>2',
+        ['Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol'],
+        'Jeff',
+    ],
+];
diff --git a/tests/data/Calculation/Statistical/COUNTIF.php b/tests/data/Calculation/Statistical/COUNTIF.php
index c0e69c6769..69277e7234 100644
--- a/tests/data/Calculation/Statistical/COUNTIF.php
+++ b/tests/data/Calculation/Statistical/COUNTIF.php
@@ -23,12 +23,55 @@
     ],
     [
         2,
-        [6, 3, 4, 'X', ''],
+        [6, 3, 4, 'X', '', null],
         '<=4',
     ],
     [
         2,
-        [6, 3, 4, 'X', ''],
+        [6, 3, 4, 31, 'X', '', null],
         '<="4"',
     ],
+    [
+        2,
+        [0, 1, 1, 2, 3, 5, 8, 0, 13, 21],
+        0,
+    ],
+    [
+        3,
+        [true, false, false, true, false, true, false, false],
+        true,
+    ],
+    [
+        5,
+        [true, false, false, true, false, true, false, false],
+        '<>true',
+    ],
+    [
+        4,
+        ['apples', 'oranges', 'peaches', 'apples'],
+        '*',
+    ],
+    [
+        3,
+        ['apples', 'oranges', 'peaches', 'apples'],
+        '*p*s*',
+    ],
+    [
+        4,
+        [
+            ['apples', 'oranges', 'peaches', 'apples'],
+            ['bananas', 'mangoes', 'grapes', 'cherries'],
+        ],
+        '*p*e*',
+    ],
+    [
+        2,
+        ['apples', 'oranges', 'peaches', 'apples'],
+        '?????es',
+    ],
+    [
+        2,
+        ['great * ratings', 'bad * ratings', 'films * wars', 'films * trek', 'music * radio'],
+        '*~* ra*s',
+    ],
 ];
diff --git a/tests/data/Calculation/Statistical/COUNTIFS.php b/tests/data/Calculation/Statistical/COUNTIFS.php
index 32f64d7138..07f96d3837 100644
--- a/tests/data/Calculation/Statistical/COUNTIFS.php
+++ b/tests/data/Calculation/Statistical/COUNTIFS.php
@@ -16,9 +16,28 @@
         ['C', 'B', 'A', 'B', 'B'],
         '=B',
     ],
+    //    [
+    //        2,
+    //        [1, 2, 3, 'B', null, '', false],
+    //        '<=2',
+    //    ],
+    //    [
+    //        2,
+    //        [1, 2, 3, 'B', null, '', false],
+    //        '<=B',
+    //    ],
+    [
+        4,
+        ['Female', 'Female', 'Female', 'Male', 'Male', 'Male', 'Female', 'Female', 'Female', 'Male', 'Male', 'Male'],
+        'Female',
+        [0.63, 0.78, 0.39, 0.55, 0.71, 0.51, 0.78, 0.81, 0.49, 0.35, 0.69, 0.65],
+        '>60%',
+    ],
     [
         2,
-        [1, 2, 3, 'B', '', false],
-        '<=2',
+        ['Maths', 'English', 'Science', 'Maths', 'English', 'Science', 'Maths', 'English', 'Science', 'Maths', 'English', 'Science'],
+        'Science',
+        [0.63, 0.78, 0.39, 0.55, 0.71, 0.51, 0.78, 0.81, 0.49, 0.35, 0.69, 0.65],
+        '<50%',
     ],
 ];
diff --git a/tests/data/Calculation/Statistical/MAXIFS.php b/tests/data/Calculation/Statistical/MAXIFS.php
index deb4bcebc4..58ed5e4672 100644
--- a/tests/data/Calculation/Statistical/MAXIFS.php
+++ b/tests/data/Calculation/Statistical/MAXIFS.php
@@ -21,6 +21,20 @@
         ],
         '=H',
     ],
+    [
+        2,
+        [
+            [1],
+            [2],
+            [3],
+        ],
+        [
+            ['Y'],
+            ['Y'],
+            ['N'],
+        ],
+        '=Y',
+    ],
     [
         2,
         [
@@ -41,4 +55,18 @@
         ],
         '=B',
     ],
+    [
+        456000,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        1,
+    ],
+    [
+        310000,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        '>2',
+        ['Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol'],
+        'Jeff',
+    ],
 ];
diff --git a/tests/data/Calculation/Statistical/MINIFS.php b/tests/data/Calculation/Statistical/MINIFS.php
index a00f25b7f8..6ecade9fdf 100644
--- a/tests/data/Calculation/Statistical/MINIFS.php
+++ b/tests/data/Calculation/Statistical/MINIFS.php
@@ -21,6 +21,20 @@
         ],
         '=H',
     ],
+    [
+        1,
+        [
+            [1],
+            [2],
+            [3],
+        ],
+        [
+            ['Y'],
+            ['Y'],
+            ['N'],
+        ],
+        '=Y',
+    ],
     [
         2,
         [
@@ -41,4 +55,18 @@
         ],
         '=B',
     ],
+    [
+        125000,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        1,
+    ],
+    [
+        261000,
+        [223000, 125000, 456000, 322000, 340000, 198000, 310000, 250000, 460000, 261000, 389000, 305000],
+        [1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4],
+        '>2',
+        ['Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol', 'Jeff', 'Chris', 'Carol'],
+        'Jeff',
+    ],
 ];