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Bug#33143: Incorrect ORDER BY for ROUND()/TRUNCATE() result

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The ROUND(X, D) function would change the Item::decimals field during
execution to achieve the effect of a dynamic number of decimal digits.
This caused a series of bugs:
Bug #30617:Round() function not working under some circumstances in InnoDB
Bug #33402:ROUND with decimal and non-constant cannot round to 0 decimal places
Bug #30889:filesort and order by with float/numeric crashes server
Fixed by never changing the number of shown digits for DECIMAL when
used with a nonconstant number of decimal digits.


mysql-test/r/type_decimal.result:
  Bug#33143: Test result
mysql-test/t/type_decimal.test:
  Bug#33143: Test case
sql/item_func.cc:
  Bug#33143: 
  - Moved the DECIMAL_MAX_SCALE limitation to fix_length_and_dec.
  - Removed resetting of Item::decimals field.
  - set the frac field of the output value to current scale.
strings/decimal.c:
  Bug#33143: It is necessary to set all digits in the buffer following the 
  rounded one to zero, as they may now be displayed.
This commit is contained in:
unknown
2008-01-14 16:16:36 +01:00
parent 62a7e160bc
commit f9440588f5
4 changed files with 125 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

63
mysql-test/r/type_decimal.result
View File

@ -797,7 +797,7 @@ dps tinyint(3) unsigned default NULL
INSERT INTO t1 VALUES (1.1325,3);
SELECT ROUND(qty,3), dps, ROUND(qty,dps) FROM t1;
ROUND(qty,3) dps ROUND(qty,dps)
1.133 3 1.133
1.133 3 1.133000
DROP TABLE t1;
SELECT 1 % .123456789123456789123456789123456789123456789123456789123456789123456789123456789 AS '%';
%
@ -805,3 +805,64 @@ SELECT 1 % .12345678912345678912345678912345678912345678912345678912345678912345
SELECT MOD(1, .123456789123456789123456789123456789123456789123456789123456789123456789123456789) AS 'MOD()';
MOD()
0.012345687012345687012345687012345687012345687012345687012345687012345687000000000
CREATE TABLE t1( a DECIMAL(4, 3), b INT );
INSERT INTO t1 VALUES ( 1, 5 ), ( 2, 4 ), ( 3, 3 ), ( 4, 2 ), ( 5, 1 );
SELECT a, b, ROUND( a, b ) AS c FROM t1 ORDER BY c;
a b c
1.000 5 1.000
2.000 4 2.000
3.000 3 3.000
4.000 2 4.000
5.000 1 5.000
SELECT a, b, ROUND( a, b ) AS c FROM t1 ORDER BY c DESC;
a b c
5.000 1 5.000
4.000 2 4.000
3.000 3 3.000
2.000 4 2.000
1.000 5 1.000
CREATE TABLE t2 ( a INT, b INT, c DECIMAL(5, 4) );
INSERT INTO t2 VALUES ( 0, 1, 1.2345 ), ( 1, 2, 1.2345 ),
( 3, 3, 1.2345 ), ( 2, 4, 1.2345 );
SELECT a, b, MAX(ROUND(c, a))
FROM t2
GROUP BY a, b
ORDER BY b;
a b MAX(ROUND(c, a))
0 1 1.0000
1 2 1.2000
3 3 1.2350
2 4 1.2300
SELECT a, b, ROUND(c, a)
FROM t2;
a b ROUND(c, a)
0 1 1.0000
1 2 1.2000
3 3 1.2350
2 4 1.2300
CREATE TABLE t3( a INT, b DECIMAL(6, 3) );
INSERT INTO t3 VALUES( 0, 1.5 );
SELECT ROUND( b, a ) FROM t3;
ROUND( b, a )
2.000
CREATE TABLE t4( a INT, b DECIMAL( 12, 0) );
INSERT INTO t4 VALUES( -9, 1.5e9 );
SELECT ROUND( b, a ) FROM t4;
ROUND( b, a )
2000000000
CREATE TABLE t5( a INT, b DECIMAL( 13, 12 ) );
INSERT INTO t5 VALUES( 0, 1.5 );
INSERT INTO t5 VALUES( 9, 1.5e-9 );
SELECT ROUND( b, a ) FROM t5;
ROUND( b, a )
2.000000000000
0.000000002000
CREATE TABLE t6( a INT );
INSERT INTO t6 VALUES( 6 / 8 );
SELECT * FROM t6;
a
1
SELECT ROUND(20061108085411.000002);
ROUND(20061108085411.000002)
20061108085411
DROP TABLE t1, t2, t3, t4, t5, t6;

43
mysql-test/t/type_decimal.test
View File

@ -416,3 +416,46 @@ DROP TABLE t1;
SELECT 1 % .123456789123456789123456789123456789123456789123456789123456789123456789123456789 AS '%';
SELECT MOD(1, .123456789123456789123456789123456789123456789123456789123456789123456789123456789) AS 'MOD()';
#
# Bug #33143: Incorrect ORDER BY for ROUND()/TRUNCATE() result
#
CREATE TABLE t1( a DECIMAL(4, 3), b INT );
INSERT INTO t1 VALUES ( 1, 5 ), ( 2, 4 ), ( 3, 3 ), ( 4, 2 ), ( 5, 1 );
SELECT a, b, ROUND( a, b ) AS c FROM t1 ORDER BY c;
SELECT a, b, ROUND( a, b ) AS c FROM t1 ORDER BY c DESC;
CREATE TABLE t2 ( a INT, b INT, c DECIMAL(5, 4) );
INSERT INTO t2 VALUES ( 0, 1, 1.2345 ), ( 1, 2, 1.2345 ),
( 3, 3, 1.2345 ), ( 2, 4, 1.2345 );
SELECT a, b, MAX(ROUND(c, a))
FROM t2
GROUP BY a, b
ORDER BY b;
SELECT a, b, ROUND(c, a)
FROM t2;
CREATE TABLE t3( a INT, b DECIMAL(6, 3) );
INSERT INTO t3 VALUES( 0, 1.5 );
SELECT ROUND( b, a ) FROM t3;
CREATE TABLE t4( a INT, b DECIMAL( 12, 0) );
INSERT INTO t4 VALUES( -9, 1.5e9 );
SELECT ROUND( b, a ) FROM t4;
CREATE TABLE t5( a INT, b DECIMAL( 13, 12 ) );
INSERT INTO t5 VALUES( 0, 1.5 );
INSERT INTO t5 VALUES( 9, 1.5e-9 );
SELECT ROUND( b, a ) FROM t5;
CREATE TABLE t6( a INT );
INSERT INTO t6 VALUES( 6 / 8 );
SELECT * FROM t6;
SELECT ROUND(20061108085411.000002);
DROP TABLE t1, t2, t3, t4, t5, t6;

12
sql/item_func.cc
View File

@ -2008,7 +2008,7 @@ void Item_func_round::fix_length_and_dec()
int length_increase= ((decimals_delta <= 0) || truncate) ? 0:1;
precision-= decimals_delta - length_increase;
decimals= decimals_to_set;
decimals= min(decimals_to_set, DECIMAL_MAX_SCALE);
max_length= my_decimal_precision_to_length(precision, decimals,
unsigned_flag);
break;
@ -2107,18 +2107,18 @@ my_decimal *Item_func_round::decimal_op(my_decimal *decimal_value)
{
my_decimal val, *value= args[0]->val_decimal(&val);
longlong dec= args[1]->val_int();
if (dec > 0 || (dec < 0 && args[1]->unsigned_flag))
{
if (dec >= 0 || args[1]->unsigned_flag)
dec= min((ulonglong) dec, DECIMAL_MAX_SCALE);
decimals= (uint8) dec; // to get correct output
}
else if (dec < INT_MIN)
dec= INT_MIN;
if (!(null_value= (args[0]->null_value || args[1]->null_value ||
my_decimal_round(E_DEC_FATAL_ERROR, value, (int) dec,
truncate, decimal_value) > 1)))
truncate, decimal_value) > 1)))
{
decimal_value->frac= decimals;
return decimal_value;
}
return 0;
}

16
strings/decimal.c
View File

@ -1595,9 +1595,21 @@ decimal_round(decimal_t *from, decimal_t *to, int scale,
x+=10;
*buf1=powers10[pos]*(x-y);
}
if (frac0 < 0)
/*
In case we're rounding e.g. 1.5e9 to 2.0e9, the decimal_digit_t's inside
the buffer are as follows.
Before <1, 5e8>
After <2, 5e8>
Hence we need to set the 2nd field to 0.
The same holds if we round 1.5e-9 to 2e-9.
*/
if (frac0 < frac1)
{
dec1 *end=to->buf+intg0, *buf=buf1+1;
dec1 *buf= to->buf + ((scale == 0 && intg0 == 0) ? 1 : intg0 + frac0);
dec1 *end= to->buf + len;
while (buf < end)
*buf++=0;
}