Re: Select last row that is less than or equal to a date

[David Marcus]

I may run this query up to 50,000 times in a PHP script on my Web server.

There are 97 rows for HistoryPlayer = 59161. There are 71 with HistoryDate <= '2012-01-01'. There are none with HistoryDate = '2012-01-01'. HistoryDate <= '2012-01-01', the returned values are

2011-12-25
2011-12-18
2011-12-11
2011-12-04
...

I did not run any other queries between what I showed you. I just tried it again and got identical results.

By the way, I now think MySQL is executing the query fine. Turns out my script was slow because I had a temporary table that I was running lots of update queries against. I didn't specify the engine, so when my hosting company upgraded to a recent version of MySQL, this became an InnoDB table. Each update was taking around 0.1 seconds. I changed it to engine=memory and now it is back to what it used to be.