expression: fix some problems related to flen (#27677)

pingcap · Sep 15, 2021 · 83445d6 · 83445d6
1 parent b1dc110
commit 83445d6
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Showing 7 changed files with 57 additions and 21 deletions.
diff --git a/expression/builtin_arithmetic.go b/expression/builtin_arithmetic.go
@@ -136,7 +136,9 @@ func (c *arithmeticDivideFunctionClass) setType4DivDecimal(retTp, a, b *types.Fi
 		retTp.Flen = mysql.MaxDecimalWidth
 		return
 	}
-	retTp.Flen = a.Flen + decb + precIncrement
+	aPrec := types.DecimalLength2Precision(a.Flen, a.Decimal, mysql.HasUnsignedFlag(a.Flag))
+	retTp.Flen = aPrec + decb + precIncrement
+	retTp.Flen = types.Precision2LengthNoTruncation(retTp.Flen, retTp.Decimal, mysql.HasUnsignedFlag(retTp.Flag))
 	if retTp.Flen > mysql.MaxDecimalWidth {
 		retTp.Flen = mysql.MaxDecimalWidth
 	}

diff --git a/expression/builtin_string.go b/expression/builtin_string.go
@@ -366,13 +366,13 @@ func (c *concatWSFunctionClass) getFunction(ctx sessionctx.Context, args []Expre
 				bf.tp.Flen = mysql.MaxBlobWidth
 				logutil.BgLogger().Warn("unexpected `Flen` value(-1) in CONCAT_WS's args", zap.Int("arg's index", i))
 			}
+			bf.tp.Flen += argType.Flen
 		}
-		bf.tp.Flen += argType.Flen
 	}
 
 	// add separator
-	argsLen := len(args) - 1
-	bf.tp.Flen += argsLen - 1
+	sepsLen := len(args) - 2
+	bf.tp.Flen += sepsLen * args[0].GetType().Flen
 
 	if bf.tp.Flen >= mysql.MaxBlobWidth {
 		bf.tp.Flen = mysql.MaxBlobWidth

diff --git a/expression/builtin_time.go b/expression/builtin_time.go
@@ -2036,6 +2036,16 @@ func (c *sysDateFunctionClass) getFunction(ctx sessionctx.Context, args []Expres
 		return nil, err
 	}
 	bf.tp.Flen, bf.tp.Decimal = 19, 0
+	if len(args) == 2 && args[1].ConstItem(ctx.GetSessionVars().StmtCtx) {
+		fsp, isNull, err := args[1].EvalInt(ctx, chunk.Row{})
+		if err != nil {
+			return nil, err
+		}
+		if !isNull && fsp > 0 {
+			bf.tp.Flen += int(fsp + 1)
+			bf.tp.Decimal = int(fsp)
+		}
+	}
 	// Illegal parameters have been filtered out in the parser, so the result is always not null.
 	bf.tp.Flag |= mysql.NotNullFlag
 

diff --git a/expression/typeinfer_test.go b/expression/typeinfer_test.go
@@ -158,8 +158,8 @@ func (s *testInferTypeSuite) createTestCase4Constants() []typeInferTestCase {
 	return []typeInferTestCase{
 		{"1", mysql.TypeLonglong, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 1, 0},
 		{"-1", mysql.TypeLonglong, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 2, 0},
-		{"1.23", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 4, 2},
-		{"-1.23", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 5, 2},
+		{"1.23", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 5, 2},
+		{"-1.23", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 6, 2},
 		{"123e5", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 8, types.UnspecifiedLength},
 		{"-123e5", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 9, types.UnspecifiedLength},
 		{"123e-5", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 7, types.UnspecifiedLength},
@@ -244,8 +244,8 @@ func (s *testInferTypeSuite) createTestCase4StrFuncs() []typeInferTestCase {
 		{"CONCAT(c_bchar, 0x80)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 23, types.UnspecifiedLength},
 		{"CONCAT('T', 'i', 'DB')", mysql.TypeVarString, charset.CharsetUTF8MB4, mysql.NotNullFlag, 4, types.UnspecifiedLength},
 		{"CONCAT('T', 'i', 'DB', c_binary)", mysql.TypeVarString, charset.CharsetBin, mysql.BinaryFlag, 24, types.UnspecifiedLength},
-		{"CONCAT_WS('-', 'T', 'i', 'DB')", mysql.TypeVarString, charset.CharsetUTF8MB4, mysql.NotNullFlag, 7, types.UnspecifiedLength},
-		{"CONCAT_WS(',', 'TiDB', c_binary)", mysql.TypeVarString, charset.CharsetBin, mysql.BinaryFlag, 26, types.UnspecifiedLength},
+		{"CONCAT_WS('-', 'T', 'i', 'DB')", mysql.TypeVarString, charset.CharsetUTF8MB4, mysql.NotNullFlag, 6, types.UnspecifiedLength},
+		{"CONCAT_WS(',', 'TiDB', c_binary)", mysql.TypeVarString, charset.CharsetBin, mysql.BinaryFlag, 25, types.UnspecifiedLength},
 		{"CONCAT(c_bchar, 0x80)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 23, types.UnspecifiedLength},
 		{"left(c_int_d, c_int_d)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 20, types.UnspecifiedLength},
 		{"right(c_int_d, c_int_d)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 20, types.UnspecifiedLength},
@@ -540,7 +540,7 @@ func (s *testInferTypeSuite) createTestCase4MathFuncs() []typeInferTestCase {
 		{"floor(c_enum)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, 0},
 		{"floor(c_text_d)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, 0},
 		{"floor(18446744073709551615)", mysql.TypeLonglong, charset.CharsetBin, mysql.NotNullFlag | mysql.UnsignedFlag | mysql.BinaryFlag, 20, 0},
-		{"floor(18446744073709551615.1)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 22, 0},
+		{"floor(18446744073709551615.1)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 23, 0},
 
 		{"ceil(c_int_d)", mysql.TypeLonglong, charset.CharsetBin, mysql.BinaryFlag, 11, 0},
 		{"ceil(c_uint_d)", mysql.TypeLonglong, charset.CharsetBin, mysql.UnsignedFlag | mysql.BinaryFlag, 10, 0},
@@ -558,7 +558,7 @@ func (s *testInferTypeSuite) createTestCase4MathFuncs() []typeInferTestCase {
 		{"ceil(c_enum)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, 0},
 		{"ceil(c_text_d)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, 0},
 		{"ceil(18446744073709551615)", mysql.TypeLonglong, charset.CharsetBin, mysql.NotNullFlag | mysql.UnsignedFlag | mysql.BinaryFlag, 20, 0},
-		{"ceil(18446744073709551615.1)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 22, 0},
+		{"ceil(18446744073709551615.1)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 23, 0},
 
 		{"ceiling(c_int_d)", mysql.TypeLonglong, charset.CharsetBin, mysql.BinaryFlag, 11, 0},
 		{"ceiling(c_decimal)", mysql.TypeLonglong, charset.CharsetBin, mysql.BinaryFlag, 6, 0},
@@ -569,7 +569,7 @@ func (s *testInferTypeSuite) createTestCase4MathFuncs() []typeInferTestCase {
 		{"ceiling(c_enum)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, 0},
 		{"ceiling(c_text_d)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, 0},
 		{"ceiling(18446744073709551615)", mysql.TypeLonglong, charset.CharsetBin, mysql.NotNullFlag | mysql.UnsignedFlag | mysql.BinaryFlag, 20, 0},
-		{"ceiling(18446744073709551615.1)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 22, 0},
+		{"ceiling(18446744073709551615.1)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 23, 0},
 
 		{"conv(c_char, c_int_d, c_int_d)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 64, types.UnspecifiedLength},
 		{"conv(c_int_d, c_int_d, c_int_d)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, 64, types.UnspecifiedLength},
@@ -730,19 +730,19 @@ func (s *testInferTypeSuite) createTestCase4ArithmeticFuncs() []typeInferTestCas
 		{"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, 15, 4},
-		{"c_int_d / c_bigint_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 15, 4},
+		{"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_char", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
-		{"c_int_d / c_time_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 15, 4},
+		{"c_int_d / c_time_d", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 16, 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, 18, 4},
+		{"c_int_d / c_decimal", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 19, 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, 27, 4}, // TODO: Flen should be 28.
+		{"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, 5, 4},
-		{"-2/3", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 6, 4},
+		{"2/3", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 6, 4},
+		{"-2/3", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag, 7, 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},
@@ -831,15 +831,15 @@ func (s *testInferTypeSuite) createTestCase4Aggregations() []typeInferTestCase {
 		{"sum(c_double_d)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"sum(c_decimal)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 28, 3},
 		{"sum(cast(c_decimal as decimal(65,3)))", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 65, 3},
-		{"sum(1.0)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 25, 1},
+		{"sum(1.0)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 26, 1},
 		{"sum(1.2e2)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"sum(c_char)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"avg(c_int_d)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 15, 4},
 		{"avg(c_float_d)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"avg(c_double_d)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"avg(c_decimal)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 10, 7},
 		{"avg(cast(c_decimal as decimal(65,3)))", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 65, 7},
-		{"avg(1.0)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 7, 5},
+		{"avg(1.0)", mysql.TypeNewDecimal, charset.CharsetBin, mysql.BinaryFlag, 8, 5},
 		{"avg(1.2e2)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"avg(c_char)", mysql.TypeDouble, charset.CharsetBin, mysql.BinaryFlag, mysql.MaxRealWidth, types.UnspecifiedLength},
 		{"group_concat(c_int_d)", mysql.TypeVarString, charset.CharsetUTF8MB4, 0, mysql.MaxBlobWidth, 0},

diff --git a/types/field_type.go b/types/field_type.go
@@ -293,6 +293,8 @@ func DefaultTypeForValue(value interface{}, tp *FieldType, char string, collate
 		tp.Tp = mysql.TypeNewDecimal
 		tp.Flen = len(x.ToString())
 		tp.Decimal = int(x.digitsFrac)
+		// Add the length for `.`.
+		tp.Flen++
 		SetBinChsClnFlag(tp)
 	case Enum:
 		tp.Tp = mysql.TypeEnum

diff --git a/types/field_type_test.go b/types/field_type_test.go
@@ -193,7 +193,7 @@ func (s *testFieldTypeSuite) TestDefaultTypeForValue(c *C) {
 		{NewTime(ZeroCoreTime, mysql.TypeDatetime, DefaultFsp), mysql.TypeDatetime, 19, 0, charset.CharsetBin, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag},
 		{NewTime(FromDate(2017, 12, 12, 12, 59, 59, 0), mysql.TypeDatetime, 3), mysql.TypeDatetime, 23, 3, charset.CharsetBin, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag},
 		{Duration{}, mysql.TypeDuration, 8, 0, charset.CharsetBin, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag},
-		{&MyDecimal{}, mysql.TypeNewDecimal, 1, 0, charset.CharsetBin, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag},
+		{&MyDecimal{}, mysql.TypeNewDecimal, 2, 0, charset.CharsetBin, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag},
 		{Enum{Name: "a", Value: 1}, mysql.TypeEnum, 1, UnspecifiedLength, charset.CharsetBin, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag},
 		{Set{Name: "a", Value: 1}, mysql.TypeSet, 1, UnspecifiedLength, charset.CharsetBin, charset.CharsetBin, mysql.BinaryFlag | mysql.NotNullFlag},
 	}

diff --git a/types/helper.go b/types/helper.go
@@ -206,3 +206,25 @@ func strToInt(str string) (int64, error) {
 	}
 	return int64(r), err
 }
+
+// DecimalLength2Precision gets the precision.
+func DecimalLength2Precision(length int, scale int, hasUnsignedFlag bool) int {
+	if scale > 0 {
+		length--
+	}
+	if hasUnsignedFlag || length > 0 {
+		length--
+	}
+	return length
+}
+
+// Precision2LengthNoTruncation gets the length.
+func Precision2LengthNoTruncation(length int, scale int, hasUnsignedFlag bool) int {
+	if scale > 0 {
+		length++
+	}
+	if hasUnsignedFlag || length > 0 {
+		length++
+	}
+	return length
+}