Commit c9bb7e1f authored by unknown's avatar unknown
Browse files

item_func.cc: 

  fix for bug#8461

  BUG 8461 - TRUNCATE returns incorrect result if 2nd argument is negative
  Reason: Both TRUNCATE/ROUND converts INTEGERS to DOUBLE and back to INTEGERS
  Changed the integer routine to work on integers only.
  This bug affects 4.1, 5.0 and 5.1
  Fixing in 4.1 will need to change the routine to handle different types individually.
  5.0 did had different routines for different types already just the INTEGER routine was bad.


sql/item_func.cc:
  fix for bug#8461
  BUG 8461 - TRUNCATE returns incorrect result if 2nd argument is negative
  Reason: TRUNCATE converts INTEGERS to DOUBLE and back to INTEGERS
  Both ROUND and TRUNCATE are affected by this.
  Changed the integer routine to work on integers only.
  This bug affects 4.1 5,0 and 5
  Fixing in 4.1 will need to change the routine to handle different types individually.
parent 26a81f6f

mysql-test/r/func_math.result

+15 −0
Original line number Diff line number Diff line
@@ -203,3 +203,18 @@ NULL 
Warnings:

Error	1365	Division by 0

set sql_mode='';

select round(111,-10);

round(111,-10)

0

select round(-5000111000111000155,-1);

round(-5000111000111000155,-1)

-5000111000111000160

select round(15000111000111000155,-1);

round(15000111000111000155,-1)

15000111000111000160

select truncate(-5000111000111000155,-1);

truncate(-5000111000111000155,-1)

-5000111000111000150

select truncate(15000111000111000155,-1);

truncate(15000111000111000155,-1)

15000111000111000150

mysql-test/t/func_math.test

+14 −0
Original line number Diff line number Diff line
@@ -141,3 +141,17 @@ select log(2,-1); 
select log(-2,1);

set sql_mode='';



#

# Bug #8461 truncate() and round() return false results 2nd argument negative.

# 

# round(a,-b) log_10(b) > a

select round(111,-10);

# round on bigint 

select round(-5000111000111000155,-1);

# round on unsigned bigint

select round(15000111000111000155,-1);

# truncate on bigint 

select truncate(-5000111000111000155,-1);

# truncate on unsigned bigint

select truncate(15000111000111000155,-1);

sql/item_func.cc

+18 −16
Original line number Diff line number Diff line
@@ -1863,28 +1863,30 @@ longlong Item_func_round::int_op() 
    return value; // integer have not digits after point



  abs_dec= -dec;

  double tmp;

  /*

    tmp2 is here to avoid return the value with 80 bit precision

    This will fix that the test round(0.1,1) = round(0.1,1) is true

  */

  volatile double tmp2;

  longlong tmp;

  

  tmp= (abs_dec < array_elements(log_10) ?

        log_10[abs_dec] : pow(10.0, (double) abs_dec));

  if(abs_dec >= array_elements(log_10_int))

    return 0;

  

  tmp= log_10_int[abs_dec];

  

  if (truncate)

  {

    if (unsigned_flag)

      tmp2= floor(ulonglong2double(value)/tmp)*tmp;

    else if (value >= 0)

      tmp2= floor(((double)value)/tmp)*tmp;

      value= (ulonglong(value)/tmp)*tmp;

    else

      tmp2= ceil(((double)value)/tmp)*tmp;

      value= (value/tmp)*tmp;

  }

  else

    tmp2= rint(((double)value)/tmp)*tmp;

  return (longlong)tmp2;

  {

    if (unsigned_flag)

      value= ((ulonglong(value)+(tmp>>1))/tmp)*tmp;

    else if ( value >= 0)

      value= ((value+(tmp>>1))/tmp)*tmp;

    else

      value= ((value-(tmp>>1))/tmp)*tmp;

  }

  return value;

}