expresssion: fix div result type infer bug if a integer type has minimum display length (#56158) (#56211)

close #55837

Author: ti-chi-bot

pkg/expression/builtin_arithmetic.go

@@ -653,7 +653,6 @@ func (c *arithmeticDivideFunctionClass) getFunction(ctx sessionctx.Context, args
 	if err := c.verifyArgs(args); err != nil {
 		return nil, err
 	}
-	lhsTp, rhsTp := args[0].GetType(), args[1].GetType()
 	lhsEvalTp, rhsEvalTp := numericContextResultType(args[0]), numericContextResultType(args[1])
 	if lhsEvalTp == types.ETReal || rhsEvalTp == types.ETReal {
 		bf, err := newBaseBuiltinFuncWithTp(ctx, c.funcName, args, types.ETReal, types.ETReal, types.ETReal)
@@ -669,6 +668,7 @@ func (c *arithmeticDivideFunctionClass) getFunction(ctx sessionctx.Context, args
 	if err != nil {
 		return nil, err
 	}
+	lhsTp, rhsTp := args[0].GetType(), args[1].GetType()
 	c.setType4DivDecimal(bf.tp, lhsTp, rhsTp)
 	sig := &builtinArithmeticDivideDecimalSig{bf}
 	sig.setPbCode(tipb.ScalarFuncSig_DivideDecimal)

pkg/expression/typeinfer_test.go

@@ -753,19 +753,19 @@ func (s *InferTypeSuite) createTestCase4ArithmeticFuncs() []typeInferTestCase {
 		{"c_double_d * c_char", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, types.UnspecifiedLength, types.UnspecifiedLength},
 		{"c_double_d * c_enum", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, types.UnspecifiedLength, types.UnspecifiedLength},
 
-		{"c_int_d / c_int_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 16, 4},
-		{"c_int_d / c_bigint_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 16, 4},
+		{"c_int_d / c_int_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 15, 4},
+		{"c_int_d / c_bigint_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 15, 4},
 		{"c_int_d / c_char", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
-		{"c_int_d / c_time_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 16, 4},
+		{"c_int_d / c_time_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 15, 4},
 		{"c_int_d / c_double_d", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
-		{"c_int_d / c_decimal", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 19, 4},
+		{"c_int_d / c_decimal", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 18, 4},
 		{"c_datetime / c_decimal", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 29, 6}, // TODO: flen should be 25.
 		{"c_bigint_d / c_decimal", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 28, 4}, // TODO: flen should be 28.
 		{"c_double_d / c_decimal", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"c_double_d / c_char", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"c_double_d / c_enum", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"2/3", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 6, 4},
-		{"-2/3", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 7, 4},
+		{"-2/3", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 6, 4},
 
 		{"c_int_d DIV c_int_d", mysql.TypeLonglong, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxIntWidth, 0},
 		{"c_uint_d DIV c_uint_d", mysql.TypeLonglong, charset.CharsetBin, mysql.UnsignedFlag | mysql.BinaryFlag, mysql.MaxIntWidth, 0},

tests/integrationtest/r/executor/issues.result

@@ -780,3 +780,9 @@ SELECT  count(`t`.`c`) FROM (`s`) JOIN `t`  GROUP BY `t`.`c`;
 count(`t`.`c`)
 170
 set @@tidb_max_chunk_size = default;
+CREATE TABLE test_55837 (col1 int(4) NOT NULL, col2 bigint(4) NOT NULL, KEY col2_index (col2));
+insert into test_55837 values(0,1725292800),(0,1725292800);
+select from_unixtime( if(col2 >9999999999, col2/1000, col2), '%Y-%m-%d %H:%i:%s') as result from test_55837;
+result
+2024-09-03 00:00:00
+2024-09-03 00:00:00

tests/integrationtest/t/executor/issues.test

@@ -582,3 +582,8 @@ insert into s values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),(1),
 SELECT /*+ stream_agg()*/ count(`t`.`c`) FROM (`s`) JOIN `t` GROUP BY `t`.`c`;
 SELECT  count(`t`.`c`) FROM (`s`) JOIN `t`  GROUP BY `t`.`c`;
 set @@tidb_max_chunk_size = default;
+
+# TestIssue55837
+CREATE TABLE test_55837 (col1 int(4) NOT NULL, col2 bigint(4) NOT NULL, KEY col2_index (col2));
+insert into test_55837 values(0,1725292800),(0,1725292800);
+select from_unixtime( if(col2 >9999999999, col2/1000, col2), '%Y-%m-%d %H:%i:%s') as result from test_55837;