expression: Fix wrong way to check for overflow (#27122) (#27417)

pingcap · Sep 6, 2021 · daa260f · daa260f
1 parent a4504d8
commit daa260f
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/expression/builtin_arithmetic_vec.go b/expression/builtin_arithmetic_vec.go
@@ -881,7 +881,7 @@ func (b *builtinArithmeticPlusIntSig) plusUS(result *chunk.Column, lhi64s, rhi64
 		if rh < 0 && uint64(-rh) > uint64(lh) {
 			return types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s + %s)", b.args[0].String(), b.args[1].String()))
 		}
-		if rh > 0 && uint64(lh) > math.MaxUint64-uint64(lh) {
+		if rh > 0 && uint64(lh) > math.MaxUint64-uint64(rh) {
 			return types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s + %s)", b.args[0].String(), b.args[1].String()))
 		}
 

diff --git a/expression/integration_test.go b/expression/integration_test.go
@@ -9216,6 +9216,12 @@ func (s *testIntegrationSuite) TestRefineArgNullValues(c *C) {
 	))
 }
 
+func (s *testIntegrationSuite) TestIssue26977(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	result := tk.MustQuery("select a + 1 as f from (select cast(0xfffffffffffffff0 as unsigned) as a union select cast(1 as unsigned)) t having f != 2;")
+	result.Check(testkit.Rows("18446744073709551601"))
+}
+
 func (s *testIntegrationSuite) TestIssue26958(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test;")