| List: | General Discussion | « Previous MessageNext Message » | |
| From: | hsv | Date: | October 16 2012 5:38pm |
| Subject: | Re: mysql logs query with indexes used to the slow-log and not logging if there is index in reverse order | ||
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>>>> 2012/10/16 12:57 -0400, Michael Dykman >>>>
your now() statement is getting executed for every row on the select. try
ptting the phrase up front
as in:
set @ut= unix_timestamp(now())
and then use that in your statement.
<<<<<<<<
Quote:
Functions that return the current date or time each are evaluated only once per query at
the start of query execution. This means that multiple references to a function such as
<file:///C:/Program%20Files/MySQL/MySQL%20Server%205.5/HELP/functions.html#function_now>NOW()
within a single query always produce the same result. (For our purposes, a single query
also includes a call to a stored program (stored routine, trigger, or event) and all
subprograms called by that program.) This principle also applies to
<file:///C:/Program%20Files/MySQL/MySQL%20Server%205.5/HELP/functions.html#function_curdate>CURDATE(),
<file:///C:/Program%20Files/MySQL/MySQL%20Server%205.5/HELP/functions.html#function_curtime>CURTIME(),
<file:///C:/Program%20Files/MySQL/MySQL%20Server%205.5/HELP/functions.html#function_utc-date>UTC_DATE(),
<file:///C:/Program%20Files/MySQL/MySQL%20Server%205.5/HELP/functions.html#function_utc-time>UTC_TIME(),
<file:///C:/Program%20Files/MySQL/MySQL%20Server%205.5/HELP/functio
ns.html#function_utc-timestamp>UTC_TIMESTAMP(), and to any of their synonyms.
