id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
17741	QuerySet.query.__str__() does not generate valid MySQL query with dates	anonymous	nobody	"If you have a date parameter in a QuerySet, the string of the query is not valid SQL in MySQL and will generate a warning.

Example (the model Entry has a DateField ""post_date""):
{{{
>>> from datetime import date
>>> from django.db import connection
>>> from myblog.models import Entry
>>> todays_entries = Entry.objects.filter(post_date=date.today()).values('id')
>>> str(todays_entries.query)
'SELECT `myblog_entry`.`id` FROM `myblog_entry` WHERE `myblog_entry`.`post_date` = 2012-02-21 '
>>> cursor = connection.cursor()
>>> cursor.execute(str(todays_entries.query))
DEBUG:django.db.backends:(0.121) SELECT `myblog_entry`.`id` FROM `myblog_entry` WHERE `myblog_entry`.`post_date` = 2012-02-21 ; args=()
Traceback (most recent call last):
  File ""<console>"", line 1, in <module>
  File ""/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py"", line 34, in execute
    return self.cursor.execute(sql, params)
  File ""/usr/local/lib/python2.7/dist-packages/django/db/backends/mysql/base.py"", line 86, in execute
    return self.cursor.execute(query, args)
  File ""/usr/lib/pymodules/python2.7/MySQLdb/cursors.py"", line 168, in execute
    if not self._defer_warnings: self._warning_check()
  File ""/usr/lib/pymodules/python2.7/MySQLdb/cursors.py"", line 82, in _warning_check
    warn(w[-1], self.Warning, 3)
Warning: Incorrect date value: '2012' for column 'post_date' at row 1
}}}

This query also fails with a warning in the MySQL command line:
{{{
> use myblog;
Database changed
> SELECT `myblog_entry`.`id` FROM `myblog_entry` WHERE `myblog_entry`.`post_date` = 2012-02-21;
Empty set, 1 warning (0.09 sec)
}}}

Putting quotes around the date solves the problem.
{{{
>>> from django.db import connection
>>> query_string = 'SELECT `myblog_entry`.`id` FROM `myblog_entry` WHERE `myblog_entry`.`post_date` = ""2012-02-21"" '
>>> cursor = connection.cursor()
>>> cursor.execute(str(todays_entries.query))
DEBUG:django.db.backends:(0.121) SELECT `myblog_entry`.`id` FROM `myblog_entry` WHERE `myblog_entry`.`post_date` = ""2012-02-21"" ; args=()
7L
}}}"	Bug	closed	Database layer (models, ORM)	1.3	Normal	invalid			Unreviewed	0	0	0	0	0	0