Commit 90cf3e78 authored by evgen@moonbone.local's avatar evgen@moonbone.local

Fix bug #14016 date_format() 2nd parameter was compared using case insensitive

collation

By default constant strings in second parameter of date_time() have case
insensitive collation. Because of this expressions date_format(f,'%m') and 
date_format(f,'%M') wrongly becomes equal, which results in choosing wrong 
column to sort by.

Now if second parameter of date_format() is constant then it's collation is 
changed to case sensitive.
parent 3042591a
......@@ -456,3 +456,11 @@ f1 f2
Warnings:
Warning 1292 Truncated incorrect date value: '2003-04-05 g'
Warning 1292 Truncated incorrect datetime value: '2003-04-05 10:11:12.101010234567'
create table t1 (f1 datetime);
insert into t1 (f1) values ("2005-01-01");
insert into t1 (f1) values ("2005-02-01");
select date_format(f1, "%m") as d1, date_format(f1, "%M") as d2 from t1 order by date_format(f1, "%M");
d1 d2
02 February
01 January
drop table t1;
......@@ -260,4 +260,12 @@ select str_to_date("2003-04-05 g", "%Y-%m-%d") as f1,
str_to_date("2003-04-05 10:11:12.101010234567", "%Y-%m-%d %H:%i:%S.%f") as f2;
--enable_ps_protocol
#
# Bug #14016
#
create table t1 (f1 datetime);
insert into t1 (f1) values ("2005-01-01");
insert into t1 (f1) values ("2005-02-01");
select date_format(f1, "%m") as d1, date_format(f1, "%M") as d2 from t1 order by date_format(f1, "%M");
drop table t1;
# End of 4.1 tests
......@@ -1528,6 +1528,16 @@ void Item_func_date_format::fix_length_and_dec()
if (args[1]->type() == STRING_ITEM)
{ // Optimize the normal case
fixed_length=1;
/*
Force case sensitive collation on format string.
This needed because format modifiers with different case,
for example %m and %M, have different meaning. Thus eq()
will distinguish them.
*/
args[1]->collation.set(
get_charset_by_csname(args[1]->collation.collation->csname,
MY_CS_BINSORT,MYF(0)), DERIVATION_COERCIBLE);
/*
The result is a binary string (no reason to use collation->mbmaxlen
This is becasue make_date_time() only returns binary strings
......
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