types: fix the bug about the wrong query result for decimal type

types/convert_test.go

@@ -243,6 +243,12 @@ func (s *testTypeConvertSuite) TestConvertType(c *C) {
  v, err = Convert("-10000", ft)
  c.Assert(terror.ErrorEqual(err, ErrOverflow), IsTrue, Commentf("err %v", err))
  c.Assert(v.(*MyDecimal).String(), Equals, "-9999.9999")
+ v, err = Convert("1,999.00", ft)
+ c.Assert(terror.ErrorEqual(err, ErrBadNumber), IsTrue, Commentf("err %v", err))
+ c.Assert(v.(*MyDecimal).String(), Equals, "0.0000")
+ v, err = Convert("1,999,999.00", ft)
+ c.Assert(terror.ErrorEqual(err, ErrBadNumber), IsTrue, Commentf("err %v", err))
+ c.Assert(v.(*MyDecimal).String(), Equals, "0.0000")
 
  // Test Datum.ToDecimal with bad number.
  d := NewDatum("hello")

types/mydecimal.go

@@ -407,7 +407,7 @@ func (d *MyDecimal) FromString(str []byte) error {
  str = str[1:]
  }
  var strIdx int
- for strIdx < len(str) && isDigit(str[strIdx]) {
+ for strIdx < len(str) && (isDigit(str[strIdx])) {
  strIdx++
  }
  digitsInt := strIdx
@@ -419,6 +419,9 @@ func (d *MyDecimal) FromString(str []byte) error {
  endIdx++
  }
  digitsFrac = endIdx - strIdx - 1
+ } else if strIdx < len(str) && (str[strIdx] != 'e' && str[strIdx] != 'E') {
+ *d = zeroMyDecimal
+ return ErrBadNumber
  } else {
  digitsFrac = 0
  endIdx = strIdx
@@ -443,8 +446,8 @@ func (d *MyDecimal) FromString(str []byte) error {
  var word int32
  var innerIdx int
  for digitsInt > 0 {
- digitsInt--
  strIdx--
+ digitsInt--
  word += int32(str[strIdx]-'0') * powers10[innerIdx]
  innerIdx++
  if innerIdx == digitsPerWord {