Fix incorrect ... LIKE '%' simplification with NULLs

datafusion/optimizer/src/simplify_expressions/expr_simplifier.rs

@@ -1476,13 +1476,28 @@ impl<'a, S: SimplifyInfo> TreeNodeRewriter for Simplifier<'a, S> {
                 negated,
                 escape_char: _,
                 case_insensitive: _,
-            }) if !is_null(&expr)
-                && matches!(
-                    pattern.as_ref(),
-                    Expr::Literal(ScalarValue::Utf8(Some(pattern_str))) if pattern_str == "%"
-                ) =>
+            }) if matches!(
+                pattern.as_ref(),
+                Expr::Literal(ScalarValue::Utf8(Some(pattern_str))) if pattern_str == "%"
+            ) || matches!(
+                pattern.as_ref(),
+                Expr::Literal(ScalarValue::LargeUtf8(Some(pattern_str))) if pattern_str == "%"
+            ) || matches!(
+                pattern.as_ref(),
+                Expr::Literal(ScalarValue::Utf8View(Some(pattern_str))) if pattern_str == "%"
+            ) =>
             {
-                Transformed::yes(lit(!negated))
+                // exp LIKE '%' is
+                //   - when exp is not NULL, it's true
+                //   - when exp is NULL, it's NULL
+                // exp NOT LIKE '%' is
+                //   - when exp is not NULL, it's false
+                //   - when exp is NULL, it's NULL
+                Transformed::yes(Expr::Case(Case {
+                    expr: Some(Box::new(Expr::IsNotNull(expr))),
+                    when_then_expr: vec![(Box::new(lit(true)), Box::new(lit(!negated)))],
+                    else_expr: None,
+                }))
             }
 
             // a is not null/unknown --> true (if a is not nullable)
@@ -2777,10 +2792,22 @@ mod tests {
         assert_no_change(regex_match(col("c1"), lit("f_o")));
 
         // empty cases
-        assert_change(regex_match(col("c1"), lit("")), lit(true));
-        assert_change(regex_not_match(col("c1"), lit("")), lit(false));
-        assert_change(regex_imatch(col("c1"), lit("")), lit(true));
-        assert_change(regex_not_imatch(col("c1"), lit("")), lit(false));
+        assert_change(
+            regex_match(col("c1"), lit("")),
+            if_not_null(col("c1"), true),
+        );
+        assert_change(
+            regex_not_match(col("c1"), lit("")),
+            if_not_null(col("c1"), false),
+        );
+        assert_change(
+            regex_imatch(col("c1"), lit("")),
+            if_not_null(col("c1"), true),
+        );
+        assert_change(
+            regex_not_imatch(col("c1"), lit("")),
+            if_not_null(col("c1"), false),
+        );
 
         // single character
         assert_change(regex_match(col("c1"), lit("x")), like(col("c1"), "%x%"));
@@ -3606,20 +3633,20 @@ mod tests {
 
     #[test]
     fn test_like_and_ilke() {
-        // test non-null values
+        // LIKE '%'
         let expr = like(col("c1"), "%");
-        assert_eq!(simplify(expr), lit(true));
+        assert_eq!(simplify(expr), if_not_null(col("c1"), true));
 
         let expr = not_like(col("c1"), "%");
-        assert_eq!(simplify(expr), lit(false));
+        assert_eq!(simplify(expr), if_not_null(col("c1"), false));
 
         let expr = ilike(col("c1"), "%");
-        assert_eq!(simplify(expr), lit(true));
+        assert_eq!(simplify(expr), if_not_null(col("c1"), true));
 
         let expr = not_ilike(col("c1"), "%");
-        assert_eq!(simplify(expr), lit(false));
+        assert_eq!(simplify(expr), if_not_null(col("c1"), false));
 
-        // test null values
+        // null_constant LIKE '%'
         let null = lit(ScalarValue::Utf8(None));
         let expr = like(null.clone(), "%");
         assert_eq!(simplify(expr), lit_bool_null());
@@ -4043,4 +4070,12 @@ mod tests {
             );
         }
     }
+
+    fn if_not_null(expr: Expr, then: bool) -> Expr {
+        Expr::Case(Case {
+            expr: Some(expr.is_not_null().into()),
+            when_then_expr: vec![(lit(true).into(), lit(then).into())],
+            else_expr: None,
+        })
+    }
 }

datafusion/sqllogictest/test_files/string/string_literal.slt

@@ -821,3 +821,11 @@ query TT
 select '   ', '|'
 ----
     |
+
+query BBB
+SELECT
+    NULL LIKE '%',
+    '' LIKE '%',
+    'a' LIKE '%'
+----
+NULL true true

datafusion/sqllogictest/test_files/string/string_query.slt.part

@@ -873,6 +873,56 @@ NULL NULL NULL NULL NULL
 #Raphael datafusionДатаФусион false false false false
 #NULL NULL NULL NULL NULL NULL
 
+# TODO (https://github.com/apache/datafusion/issues/12637) uncomment additional test projections
+query TTBB
+SELECT ascii_1, unicode_1,
+      ascii_1 LIKE '%' AS ascii_1_like_percent,
+      unicode_1 LIKE '%' AS unicode_1_like_percent
+      -- ascii_1 LIKE '%%' AS ascii_1_like_percent_percent, -- TODO enable after fixing https://github.com/apache/datafusion/issues/12637
+      -- unicode_1 LIKE '%%' AS unicode_1_like_percent_percent -- TODO enable after fixing https://github.com/apache/datafusion/issues/12637
+FROM test_basic_operator
+----
+Andrew datafusion📊🔥 true true
+Xiangpeng datafusion数据融合 true true
+Raphael datafusionДатаФусион true true
+under_score un iść core true true
+percent pan Tadeusz ma iść w kąt true true
+(empty) (empty) true true
+NULL NULL NULL NULL
+NULL NULL NULL NULL
+
+# TODO (https://github.com/apache/datafusion/issues/12637) uncomment additional test projections
+query TTBB
+SELECT ascii_1, unicode_1,
+      ascii_1 NOT LIKE '%' AS ascii_1_not_like_percent,
+      unicode_1 NOT LIKE '%' AS unicode_1_not_like_percent
+      -- ascii_1 NOT LIKE '%%' AS ascii_1_not_like_percent_percent, -- TODO enable after fixing https://github.com/apache/datafusion/issues/12637
+      -- unicode_1 NOT LIKE '%%' AS unicode_1_not_like_percent_percent -- TODO enable after fixing https://github.com/apache/datafusion/issues/12637
+FROM test_basic_operator
+----
+Andrew datafusion📊🔥 false false
+Xiangpeng datafusion数据融合 false false
+Raphael datafusionДатаФусион false false
+under_score un iść core false false
+percent pan Tadeusz ma iść w kąt false false
+(empty) (empty) false false
+NULL NULL NULL NULL
+NULL NULL NULL NULL
+
+query T
+SELECT ascii_1 FROM test_basic_operator WHERE ascii_1 LIKE '%'
+----
+Andrew
+Xiangpeng
+Raphael
+under_score
+percent
+(empty)
+
+query T
+SELECT ascii_1 FROM test_basic_operator WHERE ascii_1 NOT LIKE '%'
+----
+
 # Test pattern without wildcard characters
 query TTBBBB
 select ascii_1, unicode_1,