executor: fix ifnull bug when arg is enum/set (#25110) (#26035)

pingcap · Jul 14, 2021 · 7874d60 · 7874d60
1 parent 831cad0
commit 7874d60
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/planner/core/expression_rewriter.go b/planner/core/expression_rewriter.go
@@ -1617,9 +1617,13 @@ func (er *expressionRewriter) rewriteFuncCall(v *ast.FuncCallExpr) bool {
 		stackLen := len(er.ctxStack)
 		arg1 := er.ctxStack[stackLen-2]
 		col, isColumn := arg1.(*expression.Column)
+		var isEnumSet bool
+		if arg1.GetType().Tp == mysql.TypeEnum || arg1.GetType().Tp == mysql.TypeSet {
+			isEnumSet = true
+		}
 		// if expr1 is a column and column has not null flag, then we can eliminate ifnull on
 		// this column.
-		if isColumn && mysql.HasNotNullFlag(col.RetType.Flag) {
+		if isColumn && !isEnumSet && mysql.HasNotNullFlag(col.RetType.Flag) {
 			name := er.ctxNameStk[stackLen-2]
 			newCol := col.Clone().(*expression.Column)
 			er.ctxStackPop(len(v.Args))

diff --git a/planner/core/expression_rewriter_test.go b/planner/core/expression_rewriter_test.go
@@ -43,6 +43,16 @@ func (s *testExpressionRewriterSuite) TestIfNullEliminateColName(c *C) {
 	c.Assert(err, IsNil)
 	fields := rs.Fields()
 	c.Assert(fields[0].Column.Name.L, Equals, "ifnull(a,b)")
+
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(e int not null, b int)")
+	tk.MustExec("insert into t values(1, 1)")
+	tk.MustExec("create table t1(e int not null, b int)")
+	tk.MustExec("insert into t1 values(1, 1)")
+	rows := tk.MustQuery("select b from t where ifnull(e, b)")
+	rows.Check(testkit.Rows("1"))
+	rows = tk.MustQuery("select b from t1 where ifnull(e, b)")
+	rows.Check(testkit.Rows("1"))
 }
 
 func (s *testExpressionRewriterSuite) TestBinaryOpFunction(c *C) {