问题:

Is there any way to convert string to UNIX timestamp in MySQL?

For example I have string 2011-12-21 02:20pm which needs to be in unix timestamp format.

回答1:

UNIX_TIMESTAMP() does the trick:

SELECT UNIX_TIMESTAMP('2011-12-21 14:20:00');

However, the UNIX_TIMESTAMP() function only takes a standard MySQL formatted date. If you want to use the AM/PM notation, you will need to use STR_TO_DATE first like this:

SELECT UNIX_TIMESTAMP(
    STR_TO_DATE('2011-12-21 02:20pm', '%Y-%m-%d %h:%i%p')
);

回答2:

Though @a'r has already given the correct answer, still something I would like to add here is that the two params STR_TO_DATE() function, 'date string' format and 'date format' string, should have matching placement of '-' and ':'.

For example following 4 queries return exact same result 2014-05-28 11:30:10

SELECT STR_TO_DATE('2014-05-28 11:30:10','%Y-%m-%d %H:%i:%s');

SELECT STR_TO_DATE('20140528 11:30:10','%Y%m%d %H:%i:%s');

SELECT STR_TO_DATE('2014-05-28 113010','%Y-%m-%d %H%i%s') ;

SELECT STR_TO_DATE('20140528 113010','%Y%m%d %H%i%s');

Note: the 2 params to STR_TO_DATE() function in each query has matching placement for '-' and ':'