Date and Time Functions

mysql> SELECT something FROM tbl_name

    -> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= date_col;

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mysql> SELECT DAYOFMONTH('2001-11-00'), MONTH('2005-00-00');

        -> 0, 0

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mysql> SELECT DATE_ADD('2006-05-00',INTERVAL 1 DAY);

        -> NULL

mysql> SELECT DAYNAME('2006-05-00');

        -> NULL

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mysql> SELECT DATE_ADD('2008-01-02', INTERVAL 31 DAY);

        -> '2008-02-02'

mysql> SELECT ADDDATE('2008-01-02', INTERVAL 31 DAY);

        -> '2008-02-02'

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mysql> SELECT ADDDATE('2008-01-02', 31);

        -> '2008-02-02'

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mysql> SELECT ADDTIME('2007-12-31 23:59:59.999999', '1 1:1:1.000002');

        -> '2008-01-02 01:01:01.000001'

mysql> SELECT ADDTIME('01:00:00.999999', '02:00:00.999998');

        -> '03:00:01.999997'

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mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','GMT','MET');

        -> '2004-01-01 13:00:00'

mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','+00:00','+10:00');

        -> '2004-01-01 22:00:00'

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mysql> SELECT CURDATE();

        -> '2008-06-13'

mysql> SELECT CURDATE() + 0;

        -> 20080613

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