Re: help me, optimize a long running query

[h ch]

date_format(date_add(now(), interval -7 day),'%Y-%m-%d')
can not be simplified to
date_add(now(), interval -7 day)

i find the result is different under mysql 5.0.22 and other mysql version(5.0.45,5.0.77)

in mysql 5.0.22

mysql> select pubDate from trade where pubDate=date_add(now(),interval - 1 day) limit 1;
+------------+
| pubDate |
+------------+
| 2011-12-26 |
+------------+
1 row in set (0.00 sec)

in mysql 5.0.45

mysql> select pubDate from trade where pubDate=date_add(now(),interval - 1 day) limit 1;
Empty set (0.08 sec)

mysql> select pubDate from trade where pubDate='2011-12-26' limit 1;
+------------+
| pubDate |
+------------+
| 2011-12-26 |
+------------+
1 row in set (0.27 sec)