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Bug #45386: Wrong query result with MIN function in field list,

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WHERE and GROUP BY clause

Loose index scan may use range conditions on the argument of 
the MIN/MAX aggregate functions to find the beginning/end of 
the interval that satisfies the range conditions in a single go.
These range conditions may have open or closed minimum/maximum 
values. When the comparison returns 0 (equal) the code should 
check the type of the min/max values of the current interval 
and accept or reject the row based on whether the limit is 
open or not.
There was a wrong composite condition on checking this and it was
not working in all cases.
Fixed by simplifying the conditions and reversing the logic.
This commit is contained in:
Georgi Kodinov
2009-06-12 15:38:55 +03:00
parent 425790610d
commit 1f2b5b3037
3 changed files with 90 additions and 4 deletions
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20
sql/opt_range.cc
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@ -9395,8 +9395,14 @@ int QUICK_GROUP_MIN_MAX_SELECT::next_min_in_range()
/* Compare the found key with max_key. */
int cmp_res= key_cmp(index_info->key_part, max_key,
real_prefix_len + min_max_arg_len);
if (!(((cur_range->flag & NEAR_MAX) && (cmp_res == -1)) ||
(cmp_res <= 0)))
/*
The key is outside of the range if:
the interval is open and the key is equal to the maximum boundry
or
the key is greater than the maximum
*/
if (((cur_range->flag & NEAR_MAX) && cmp_res == 0) ||
cmp_res > 0)
{
result = HA_ERR_KEY_NOT_FOUND;
continue;
@ -9511,8 +9517,14 @@ int QUICK_GROUP_MIN_MAX_SELECT::next_max_in_range()
/* Compare the found key with min_key. */
int cmp_res= key_cmp(index_info->key_part, min_key,
real_prefix_len + min_max_arg_len);
if (!(((cur_range->flag & NEAR_MIN) && (cmp_res == 1)) ||
(cmp_res >= 0)))
/*
The key is outside of the range if:
the interval is open and the key is equal to the minimum boundry
or
the key is less than the minimum
*/
if (((cur_range->flag & NEAR_MIN) && cmp_res == 0) ||
cmp_res < 0)
continue;
}
/* If we got to this point, the current key qualifies as MAX. */