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author | unknown <mhansson/martin@linux-st28.site> | 2007-05-15 15:29:12 +0300 |
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committer | unknown <mhansson/martin@linux-st28.site> | 2007-05-15 15:29:12 +0300 |
commit | aaf6acae9be9b732c023a7d7ce94cb66f4a61de6 (patch) | |
tree | 56b80b70ec60a2d2a552a5513a6132a311e2dd4c /bdb/db_upgrade | |
parent | d03c7d2d28fe86d88c30f8799b78cf966e5a3ab7 (diff) | |
download | mariadb-git-aaf6acae9be9b732c023a7d7ce94cb66f4a61de6.tar.gz |
Bug#27573: MIN() on an indexed column which is always NULL sets _other_ results
to NULL
For queries of the form SELECT MIN(key_part_k) FROM t1
WHERE key_part_1 = const and ... and key_part_k-1 = const,
the opt_sum_query optimization tries to
use an index to substitute MIN/MAX functions with their values according
to the following rules:
1) Insert the minimum non-null values where the WHERE clause still matches, or
3) A row of nulls
However, the correct semantics requires that there is a third case 2)
such that a NULL value is substituted if there are only NULL values for
key_part_k.
The patch modifies opt_sum_query() to handle this missing case.
mysql-test/r/func_group.result:
Bug #27573: Correct result
mysql-test/t/func_group.test:
Bug #27573: test case
sql/opt_sum.cc:
Bug #27573:
Added code that will try to read the
first non-null value for a given complete-field prefix, second
choice is to read the null, and lastly set the error code if no row
is found.
Diffstat (limited to 'bdb/db_upgrade')
0 files changed, 0 insertions, 0 deletions