planner: set enumsetasint if original value is int in point get (#57550)

close #56832

Author: xhebox

pkg/planner/core/point_get_plan.go

@@ -2007,7 +2007,11 @@ func buildOrderedList(ctx base.PlanContext, plan base.Plan, list []*ast.Assignme
 		if err != nil {
 			return nil, true
 		}
-		expr = expression.BuildCastFunction(ctx.GetExprCtx(), expr, col.GetStaticType())
+		castToTP := col.GetStaticType()
+		if castToTP.GetType() == mysql.TypeEnum && assign.Expr.GetType().EvalType() == types.ETInt {
+			castToTP.AddFlag(mysql.EnumSetAsIntFlag)
+		}
+		expr = expression.BuildCastFunction(ctx.GetExprCtx(), expr, castToTP)
 		if allAssignmentsAreConstant {
 			_, isConst := expr.(*expression.Constant)
 			allAssignmentsAreConstant = isConst

pkg/planner/core/point_get_plan_test.go

@@ -275,3 +275,14 @@ func TestIssue52592(t *testing.T) {
 		"TableDual 0.00 root  rows:0",
 	))
 }
+
+func TestIssue56832(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t (id int primary key, c enum('0', '1', '2'));")
+	tk.MustExec("insert into t values (0,'0'), (1,'1'), (2,'2');")
+	tk.MustExec("update t set c = 2 where id = 0;")
+	tk.MustQuery("select c from t where id = 0").Check(testkit.Rows("1"))
+}