planner: fix wrong range calculation for Nulleq function on Enum values (#32440)

planner/core/integration_test.go

@@ -3378,6 +3378,28 @@ func (s *testIntegrationSuite) TestIssue26719(c *C) {
 	tk.MustExec(`rollback`)
 }
 
+func (s *testIntegrationSuite) TestIssue32428(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("create table `t1` (`a` enum('aa') DEFAULT NULL, KEY `k` (`a`))")
+	tk.MustExec("insert into t1 values('aa')")
+	tk.MustExec("insert into t1 values(null)")
+	tk.MustQuery("select a from t1 where a<=>'aa'").Check(testkit.Rows("aa"))
+	tk.MustQuery("select a from t1 where a<=>null").Check(testkit.Rows("<nil>"))
+
+	tk.MustExec(`CREATE TABLE IDT_MULTI15860STROBJSTROBJ (
+	  COL1 enum('aa') DEFAULT NULL,
+	  COL2 int(41) DEFAULT NULL,
+	  COL3 year(4) DEFAULT NULL,
+	  KEY U_M_COL4 (COL1,COL2),
+	  KEY U_M_COL5 (COL3,COL2))`)
+	tk.MustExec(`insert into IDT_MULTI15860STROBJSTROBJ  values("aa", 1013610488, 1982)`)
+	tk.MustQuery(`SELECT * FROM IDT_MULTI15860STROBJSTROBJ t1 RIGHT JOIN IDT_MULTI15860STROBJSTROBJ t2 ON t1.col1 <=> t2.col1 where t1.col1 is null and t2.col1 = "aa"`).Check(testkit.Rows()) // empty result
+	tk.MustExec(`prepare stmt from "SELECT * FROM IDT_MULTI15860STROBJSTROBJ t1 RIGHT JOIN IDT_MULTI15860STROBJSTROBJ t2 ON t1.col1 <=> t2.col1 where t1.col1 is null and t2.col1 = ?"`)
+	tk.MustExec(`set @a="aa"`)
+	tk.MustQuery(`execute stmt using @a`).Check(testkit.Rows()) // empty result
+}
+
 func (s *testIntegrationSerialSuite) TestPushDownProjectionForTiFlash(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")

planner/core/prepare_test.go

@@ -2390,8 +2390,7 @@ func (s *testPrepareSerialSuite) TestIssue30100(c *C) {
 	tk.MustExec("set @a=0;")
 	tk.MustQuery("execute stmt using @a").Check(testkit.Rows())
 	tk.MustQuery("execute stmt using @a").Check(testkit.Rows())
-	// If the plan contains the tableDual, it can not be cached.
-	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
 }
 
 func (s *testPlanSerialSuite) TestPartitionTable(c *C) {

util/ranger/points.go

@@ -458,6 +458,10 @@ func handleEnumFromBinOp(sc *stmtctx.StatementContext, ft *types.FieldType, val
 		res = append(res, &point{value: d, excl: false, start: false})
 	}
 
+	if op == ast.NullEQ && val.IsNull() {
+		res = append(res, &point{start: true}, &point{}) // null point
+	}
+
 	tmpEnum := types.Enum{}
 	for i := 0; i <= len(ft.Elems); i++ {
 		if i == 0 {
@@ -486,7 +490,7 @@ func handleEnumFromBinOp(sc *stmtctx.StatementContext, ft *types.FieldType, val
 				if v >= 0 {
 					appendPointFunc(d)
 				}
-			case ast.EQ:
+			case ast.EQ, ast.NullEQ:
 				if v == 0 {
 					appendPointFunc(d)
 				}