SQL: Date

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SELECT something FROM tbl_name
    -> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= date_col;

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SELECT DAYOFMONTH('2001-11-00'), MONTH('2005-00-00');
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SELECT ADDDATE('1998-01-02', 31);
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SELECT CURDATE();
        -> '1997-12-15'
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mysql> SELECT CURDATE() + 0;
        -> 19971215

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mysql> SELECT DATEDIFF('1997-12-31 23:59:59','1997-12-30');
        -> 1

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mysql> SELECT INTERVAL 1 DAY + '1997-12-31';
        -> '1998-01-01'

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mysql> SELECT DAYOFMONTH('1998-02-03');
        -> 3

//mysql> SELECT DAYOFWEEK('1998-02-03');
        -> 3

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mysql> SELECT EXTRACT(YEAR FROM '1999-07-02');
       -> 1999

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mysql> SELECT EXTRACT(YEAR_MONTH FROM '1999-07-02 01:02:03');
       -> 199907

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mysql> SELECT EXTRACT(DAY_MINUTE FROM '1999-07-02 01:02:03');
       -> 20102


//mysql> SELECT LAST_DAY('2003-02-05');
        -> '2003-02-28'

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mysql> SELECT MONTH('1998-02-03');
        -> 2

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mysql> SELECT MONTHNAME('1998-02-05');
        -> 'February'

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mysql> SELECT WEEK('1998-02-20');
        -> 7


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mysql> SELECT YEAR('2000-01-01'), WEEK('2000-01-01',0);
        -> 2000, 0

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