Question

These queries require the string to date conversion because Timestamp is stored as a string, and the logging application is unchangeable.

I have a select query that works perfectly ->

(SELECT main.user_id, main.Timestamp
FROM `user_table` main
WHERE STR_To_DATE( main.Timestamp , '%a %b %d %H:%i:%s CST %Y' ) <
  (SELECT  MAX(STR_To_DATE( sub.Timestamp , '%a %b %d %H:%i:%s CST %Y' )) 
   FROM `user_table` sub
   WHERE sub.user_id = main.user_id ))

This will select ALL BUT most recently added user id and timestamp from my table.

However, when I try to insert this into another table…like so ->

INSERT INTO user_table_temp (`user_id`, `Timestamp`)
(SELECT main.user_id, main.Timestamp
FROM `user_table` main
WHERE STR_To_DATE( main.Timestamp , '%a %b %d %H:%i:%s CST %Y' ) <
  (SELECT  MAX(STR_To_DATE( sub.Timestamp , '%a %b %d %H:%i:%s CST %Y' )) 
   FROM `user_table` sub
   WHERE sub.user_id = main.user_id ))

I get the following error ->

#1411 - Incorrect datetime value: 'Mon Mar 14 16:10:10 CDT 2011' for function str_to_date

The reason for this is because my Timestamps are stored in two formats. One will store as ‘CST’ during non-daylight-savings time, the other will store as ‘CDT’ during daylight-savings time. When the INSERT INTO SELECT gets to the first row that has the opposite of what I’m querying against, it will fail with the above message.

I have also tried to COALESCE them, which also works when just running the select ->

INSERT INTO user_table_temp  (`user_id `, `Timestamp`)
(SELECT main.user_id , main.Timestamp
FROM `user_table` main
WHERE COALESCE(STR_To_DATE( main.Timestamp , '%a %b %d %H:%i:%s CDT %Y' ), STR_To_DATE( main.Timestamp , '%a %b %d %H:%i:%s CST %Y' )) <
  (SELECT  MAX(COALESCE(STR_To_DATE( sub.Timestamp , '%a %b %d %H:%i:%s CDT %Y' ), STR_To_DATE( sub.Timestamp , '%a %b %d %H:%i:%s CST %Y' ))) 
   FROM `user_table` sub
   WHERE sub.user_id = main.user_id ))

Why would this fail on an INSERT, but the SELECT would work?

Answer 1

I think it fails on INSERT because you’re not using a supported format. The supported formats . . .

As a string in either ‘YYYY-MM-DD HH:MM:SS’ or ‘YY-MM-DD HH:MM:SS’
format. A “relaxed” syntax is permitted here, too: Any punctuation
character may be used as the delimiter between date parts or time
parts. For example, ‘2012-12-31 11:30:45’, ‘2012^12^31 11+30+45’,
‘2012/12/31 11*30*45’, and ‘2012@12@31 11^30^45’ are equivalent.

As a string with no delimiters in either ‘YYYYMMDDHHMMSS’ or
‘YYMMDDHHMMSS’ format, provided that the string makes sense as a date.
For example, ‘20070523091528’ and ‘070523091528’ are interpreted as
‘2007-05-23 09:15:28’, but ‘071122129015’ is illegal (it has a
nonsensical minute part) and becomes ‘0000-00-00 00:00:00’.

As a number in either YYYYMMDDHHMMSS or YYMMDDHHMMSS format, provided
that the number makes sense as a date. For example, 19830905132800 and
830905132800 are interpreted as ‘1983-09-05 13:28:00’.