expression: fix DIV with decimal type (#11804) (#11812)

pingcap · Aug 21, 2019 · 79d1f0b · 79d1f0b
1 parent 98714ab
commit 79d1f0b
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Showing 2 changed files with 31 additions and 4 deletions.
diff --git a/expression/builtin_arithmetic.go b/expression/builtin_arithmetic.go
@@ -763,11 +763,30 @@ func (s *builtinArithmeticIntDivideDecimalSig) evalInt(row chunk.Row) (ret int64
 		return 0, true, errors.Trace(err)
 	}
 
-	ret, err = c.ToInt()
-	// err returned by ToInt may be ErrTruncated or ErrOverflow, only handle ErrOverflow, ignore ErrTruncated.
-	if err == types.ErrOverflow {
-		return 0, true, types.ErrOverflow.GenWithStackByArgs("BIGINT", fmt.Sprintf("(%s DIV %s)", s.args[0].String(), s.args[1].String()))
+	isLHSUnsigned := mysql.HasUnsignedFlag(s.args[0].GetType().Flag)
+	isRHSUnsigned := mysql.HasUnsignedFlag(s.args[1].GetType().Flag)
+
+	if isLHSUnsigned || isRHSUnsigned {
+		val, err := c.ToUint()
+		// err returned by ToUint may be ErrTruncated or ErrOverflow, only handle ErrOverflow, ignore ErrTruncated.
+		if err == types.ErrOverflow {
+			v, err := c.ToInt()
+			// when the final result is at (-1, 0], it should be return 0 instead of the error
+			if v == 0 && err == types.ErrTruncated {
+				ret = int64(0)
+				return ret, false, nil
+			}
+			return 0, true, types.ErrOverflow.GenWithStackByArgs("BIGINT UNSIGNED", fmt.Sprintf("(%s DIV %s)", s.args[0].String(), s.args[1].String()))
+		}
+		ret = int64(val)
+	} else {
+		ret, err = c.ToInt()
+		// err returned by ToInt may be ErrTruncated or ErrOverflow, only handle ErrOverflow, ignore ErrTruncated.
+		if err == types.ErrOverflow {
+			return 0, true, types.ErrOverflow.GenWithStackByArgs("BIGINT", fmt.Sprintf("(%s DIV %s)", s.args[0].String(), s.args[1].String()))
+		}
 	}
+
 	return ret, false, nil
 }
 

diff --git a/expression/builtin_arithmetic_test.go b/expression/builtin_arithmetic_test.go
@@ -441,6 +441,14 @@ func (s *testEvaluatorSuite) TestArithmeticIntDivide(c *C) {
 			args:   []interface{}{int64(-9223372036854775808), float64(-1)},
 			expect: []interface{}{nil, "*BIGINT value is out of range in '\\(-9223372036854775808 DIV -1\\)'"},
 		},
+		{
+			args:   []interface{}{uint64(1), float64(-2)},
+			expect: []interface{}{0, nil},
+		},
+		{
+			args:   []interface{}{uint64(1), float64(-1)},
+			expect: []interface{}{nil, "*BIGINT UNSIGNED value is out of range in '\\(1 DIV -1\\)'"},
+		},
 	}
 
 	for _, tc := range testCases {