Support CASE statement in one more grammer (#262)

* Reassign condition expressions of the items in case express

* Added UT and IT

* Fixed the JDBC formatter for the case statement

* Added IT to test JDBC formatter for the case when statement

* Updated the release notes

opendistro-elasticsearch-sql.release-notes

@@ -5,6 +5,9 @@
 * Feature [#258](https://github.com/opendistro-for-elasticsearch/sql/issues/185): Elasticsearch 7.3.2 compatibility
 * Feature [#201](https://github.com/opendistro-for-elasticsearch/sql/pull/201): Improve query verification by adding semantic analyzer
 
+* Enhancement [#262](https://github.com/opendistro-for-elasticsearch/sql/pull/262): Support CASE statement in one more grammer
+* Enhancement [#253](https://github.com/opendistro-for-elasticsearch/sql/pull/253): Support Cast function
+* Enhancement [#260](https://github.com/opendistro-for-elasticsearch/sql/pull/260): Support string operators: ASCII, RTRIM, LTRIM, LOCATE, LENGTH, REPLACE
 * Enhancement [#254](https://github.com/opendistro-for-elasticsearch/sql/issues/254): Support SELECT <number_literal>
 * Enhancement [#251](https://github.com/opendistro-for-elasticsearch/sql/pull/251): Support number operators: POWER, ATAN2, COT, SIGN/SIGNUM
 * Enhancement [#215](https://github.com/opendistro-for-elasticsearch/sql/issues215): Support ordinal in GROUP/ORDER BY clause
@@ -19,6 +22,7 @@
 * Enhancement [#82](https://github.com/opendistro-for-elasticsearch/sql/issues/82): Pre-verification before actual execution of query
 * Enhancement [#75](https://github.com/opendistro-for-elasticsearch/sql/issues/75): Support order by on SQL functions like SUM etc
 
+* BugFix [#265](https://github.com/opendistro-for-elasticsearch/sql/pull/265): Fix the LOG function that delivered inaccurate result
 * BugFix [#233](https://github.com/opendistro-for-elasticsearch/sql/issues/233): Function names are case-sensitive
 * BugFix [#191](https://github.com/opendistro-for-elasticsearch/sql/issues/191): Fix new syntax check for LEFT JOIN on nested field and metadata field
 * BugFix [#188](https://github.com/opendistro-for-elasticsearch/sql/issues/188): Having doesn't working on nested field
@@ -34,9 +38,10 @@
 * BugFix [#121](https://github.com/opendistro-for-elasticsearch/sql/issues/121): Dot/period at start of index name fails to parse
 * BugFix [#111](https://github.com/opendistro-for-elasticsearch/sql/issues/111): JDBC format of aggregation query with date_format adds unnecessary column bug
 
-## 2019-10-15, Version 1.2.1 (Current)
+## 2019-10-15, Version 1.2.1
 
 ### Notable changes
+
 * Feature [#202](https://github.com/opendistro-for-elasticsearch/sql/issues/202): Elasticsearch 7.2.1 compatibility
 
 ## 2019-07-23, Version 1.2.0

src/main/java/com/amazon/opendistroforelasticsearch/sql/executor/format/SelectResultSet.java

@@ -15,6 +15,7 @@
 
 package com.amazon.opendistroforelasticsearch.sql.executor.format;
 
+import com.alibaba.druid.sql.ast.expr.SQLCaseExpr;
 import com.alibaba.druid.sql.ast.expr.SQLCastExpr;
 import com.amazon.opendistroforelasticsearch.sql.domain.Field;
 import com.amazon.opendistroforelasticsearch.sql.domain.JoinSelect;
@@ -326,6 +327,8 @@ private Schema.Type fetchMethodReturnType(Field field) {
                 if (field.getExpression() instanceof SQLCastExpr) {
                     return SQLFunctions.getCastFunctionReturnType(
                             ((SQLCastExpr) field.getExpression()).getDataType().getName());
+                } else if (field.getExpression() instanceof SQLCaseExpr) {
+                    return Schema.Type.TEXT;
                 }
                 return SQLFunctions.getScriptFunctionReturnType(
                         ((ScriptMethodField) field).getFunctionName());

src/main/java/com/amazon/opendistroforelasticsearch/sql/parser/CaseWhenParser.java

@@ -16,6 +16,8 @@
 package com.amazon.opendistroforelasticsearch.sql.parser;
 
 import com.alibaba.druid.sql.ast.SQLExpr;
+import com.alibaba.druid.sql.ast.expr.SQLBinaryOpExpr;
+import com.alibaba.druid.sql.ast.expr.SQLBinaryOperator;
 import com.alibaba.druid.sql.ast.expr.SQLCaseExpr;
 import com.alibaba.druid.sql.ast.expr.SQLNullExpr;
 import com.amazon.opendistroforelasticsearch.sql.domain.Condition;
@@ -45,6 +47,16 @@ public CaseWhenParser(SQLCaseExpr caseExpr, String alias, String tableAlias) {
     public String parse() throws SqlParseException {
         List<String> result = new ArrayList<>();
 
+        if (caseExpr.getValueExpr() != null) {
+            for (SQLCaseExpr.Item item : caseExpr.getItems()) {
+                SQLExpr left = caseExpr.getValueExpr();
+                SQLExpr right = item.getConditionExpr();
+                SQLBinaryOpExpr conditionExpr = new SQLBinaryOpExpr(left, SQLBinaryOperator.Equality, right);
+                item.setConditionExpr(conditionExpr);
+            }
+            caseExpr.setValueExpr(null);
+        }
+
         for (SQLCaseExpr.Item item : caseExpr.getItems()) {
             SQLExpr conditionExpr = item.getConditionExpr();
 

src/main/java/com/amazon/opendistroforelasticsearch/sql/parser/WhereParser.java

@@ -102,10 +102,10 @@ public void parseWhere(SQLExpr expr, Where where) throws SqlParseException {
 
         if (expr instanceof SQLBinaryOpExpr) {
             SQLBinaryOpExpr bExpr = (SQLBinaryOpExpr) expr;
-            if (explanSpecialCondWithBothSidesAreLiterals(bExpr, where)) {
+            if (explainSpecialCondWithBothSidesAreLiterals(bExpr, where)) {
                 return;
             }
-            if (explanSpecialCondWithBothSidesAreProperty(bExpr, where)) {
+            if (explainSpecialCondWithBothSidesAreProperty(bExpr, where)) {
                 return;
             }
         }
@@ -118,7 +118,7 @@ public void parseWhere(SQLExpr expr, Where where) throws SqlParseException {
             parseWhere(((SQLNotExpr) expr).getExpr(), where);
             negateWhere(where);
         } else {
-            explanCond("AND", expr, where);
+            explainCond("AND", expr, where);
         }
     }
 
@@ -135,7 +135,7 @@ private void negateWhere(Where where) throws SqlParseException {
     }
 
     //some where conditions eg. 1=1 or 3>2 or 'a'='b'
-    private boolean explanSpecialCondWithBothSidesAreLiterals(SQLBinaryOpExpr bExpr, Where where)
+    private boolean explainSpecialCondWithBothSidesAreLiterals(SQLBinaryOpExpr bExpr, Where where)
             throws SqlParseException {
         if ((bExpr.getLeft() instanceof SQLNumericLiteralExpr || bExpr.getLeft() instanceof SQLCharExpr)
                 && (bExpr.getRight() instanceof SQLNumericLiteralExpr || bExpr.getRight() instanceof SQLCharExpr)
@@ -150,14 +150,14 @@ private boolean explanSpecialCondWithBothSidesAreLiterals(SQLBinaryOpExpr bExpr,
                             + " " + operator + " " + Util.expr2Object(bExpr.getRight(), "'"))
             );
 
-            explanCond("AND", sqlMethodInvokeExpr, where);
+            explainCond("AND", sqlMethodInvokeExpr, where);
             return true;
         }
         return false;
     }
 
     //some where conditions eg. field1=field2 or field1>field2
-    private boolean explanSpecialCondWithBothSidesAreProperty(SQLBinaryOpExpr bExpr, Where where)
+    private boolean explainSpecialCondWithBothSidesAreProperty(SQLBinaryOpExpr bExpr, Where where)
             throws SqlParseException {
         //join is not support
         if ((bExpr.getLeft() instanceof SQLPropertyExpr || bExpr.getLeft() instanceof SQLIdentifierExpr)
@@ -185,7 +185,7 @@ private boolean explanSpecialCondWithBothSidesAreProperty(SQLBinaryOpExpr bExpr,
             sqlMethodInvokeExpr.addParameter(new SQLCharExpr(
                     "doc['" + leftProperty + "'].value " + operator + " doc['" + rightProperty + "'].value"));
 
-            explanCond("AND", sqlMethodInvokeExpr, where);
+            explainCond("AND", sqlMethodInvokeExpr, where);
             return true;
         }
         return false;
@@ -226,11 +226,11 @@ private void routeCond(SQLBinaryOpExpr bExpr, SQLExpr sub, Where where) throws S
             parseWhere(((SQLNotExpr) sub).getExpr(), subWhere);
             negateWhere(subWhere);
         } else {
-            explanCond(bExpr.getOperator().name, sub, where);
+            explainCond(bExpr.getOperator().name, sub, where);
         }
     }
 
-    private void explanCond(String opear, SQLExpr expr, Where where) throws SqlParseException {
+    private void explainCond(String opear, SQLExpr expr, Where where) throws SqlParseException {
         if (expr instanceof SQLBinaryOpExpr) {
             SQLBinaryOpExpr soExpr = (SQLBinaryOpExpr) expr;
             boolean methodAsOpear = false;

src/test/java/com/amazon/opendistroforelasticsearch/sql/esintgtest/QueryIT.java

@@ -1740,6 +1740,32 @@ public void backticksQuotedAliasInJDBCResponseTest() {
         assertTrue(response.contains("\"alias\": \"name\""));
     }
 
+    @Test
+    public void caseWhenSwitchTest() throws IOException {
+        JSONObject response = executeQuery("SELECT CASE age " +
+                "WHEN '30' THEN '1' " +
+                "WHEN '40' THEN '2' " +
+                "ELSE '0' END AS cases FROM " + TEST_INDEX_ACCOUNT + " WHERE age IS NOT NULL");
+        JSONObject hit = getHits(response).getJSONObject(0);
+        String age = hit.query("/_source/age").toString();
+        String cases = age.equals("30") ? "1" : age.equals("40") ? "2" : "0";
+
+        assertThat(cases, equalTo(hit.query("/fields/cases/0")));
+    }
+
+    @Test
+    public void caseWhenJdbcResponseTest() {
+        String response = executeQuery("SELECT CASE age " +
+                "WHEN '30' THEN 'age is 30' " +
+                "WHEN '40' THEN 'age is 40' " +
+                "ELSE 'NA' END AS cases FROM " + TEST_INDEX_ACCOUNT + " WHERE age is not null", "jdbc");
+        assertTrue(
+                response.contains("age is 30") ||
+                        response.contains("age is 40") ||
+                        response.contains("NA")
+        );
+    }
+
     private String getScrollId(JSONObject response) {
         return response.getString("_scroll_id");
     }

src/test/java/com/amazon/opendistroforelasticsearch/sql/unittest/parser/SqlParserTest.java

@@ -36,7 +36,9 @@
 import com.amazon.opendistroforelasticsearch.sql.parser.SqlParser;
 import com.amazon.opendistroforelasticsearch.sql.query.maker.QueryMaker;
 import com.amazon.opendistroforelasticsearch.sql.query.multi.MultiQuerySelect;
+import com.amazon.opendistroforelasticsearch.sql.util.CheckScriptContents;
 import org.elasticsearch.index.query.BoolQueryBuilder;
+import org.elasticsearch.search.builder.SearchSourceBuilder.ScriptField;
 import org.junit.Assert;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -1116,6 +1118,22 @@ public void caseWhenTestWithouhtElseExpr() throws SqlParseException {
 
     }
 
+    @Test
+    public void caseWhenSwitchTest()  {
+        String query = "SELECT CASE weather "
+                     + "WHEN 'Sunny' THEN '0' "
+                     + "WHEN 'Rainy' THEN '1' "
+                     + "ELSE 'NA' END AS case "
+                     + "FROM t";
+        ScriptField scriptField = CheckScriptContents.getScriptFieldFromQuery(query);
+        Assert.assertTrue(
+                CheckScriptContents.scriptContainsString(
+                        scriptField,
+                        "doc['weather'].value=='Sunny'"
+                )
+        );
+    }
+
     @Test
     public void castToIntTest() throws Exception {
         String query = "select cast(age as int) from "+ TestsConstants.TEST_INDEX_ACCOUNT + "/account limit 10";