Commit 84a572aa authored by holyfoot/hf@mysql.com/hfmain.(none)'s avatar holyfoot/hf@mysql.com/hfmain.(none)
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Bug #27984 Long Decimal Maths produces truncated results. 

decimal_round failed to perform a correct rounding 
of a decimal number if its first nine digits were '9'.
It just sets those digits to 0.
parent bb089cea

mysql-test/r/type_newdecimal.result

+3 −0
Original line number Diff line number Diff line
@@ -1465,4 +1465,7 @@ Error 1264 Out of range value adjusted for column 'cast(a as DECIMAL(3,2))' at r 
Error	1264	Out of range value adjusted for column 'cast(a as DECIMAL(3,2))' at row 1

Error	1264	Out of range value adjusted for column 'cast(a as DECIMAL(3,2))' at row 1

Error	1264	Out of range value adjusted for column 'cast(a as DECIMAL(3,2))' at row 1

SELECT 1.000000000000 * 99.999999999998 / 100 a,1.000000000000 * (99.999999999998 / 100) b;

a	b

0.9999999999999800000000000000	0.9999999999999800000000000000

End of 5.0 tests

mysql-test/t/type_newdecimal.test

+5 −0
Original line number Diff line number Diff line
@@ -1149,4 +1149,9 @@ select cast(a as DECIMAL(3,2)), count(*) 
  UNION select 12.1234

 ) t group by 1;



#

# Bug #27984 Long Decimal Maths produces truncated results 

#



SELECT 1.000000000000 * 99.999999999998 / 100 a,1.000000000000 * (99.999999999998 / 100) b;

--echo End of 5.0 tests

strings/decimal.c

+2 −1
Original line number Diff line number Diff line
@@ -1517,9 +1517,10 @@ decimal_round(decimal_t *from, decimal_t *to, int scale, 
    dec1 *p0= buf0+intg0+max(frac1, frac0);

    dec1 *p1= buf1+intg1+max(frac1, frac0);



    to->buf[0]= 0;

    while (buf0 < p0)

      *(--p1) = *(--p0);

    if (unlikely(intg1 > intg0))

      to->buf[0]= 0;



    intg0= intg1;

    buf0=to->buf;