If there is a sheet product has a field add_time, its data type is datetime, someone might write sql:
select * from product where add_time = '2013-01-12'
For this statement, if you store format is YY-mm-dd is the case, then OK, if you store the format: 2013-01-12 23:23:56 this format you on the tragedy, which is you can use dATE () function is used to return part of the date, so this should be a process sql:
select * from product where Date(add_time) = '2013-01-12'
If the date + time according to mode (2013-01-1223: 23: 56- time accurate to the second) query the database, the timestamp can be used () function to query:
select * from product where timestamp(add_time) = '2013-01-12 23:23:56'；
Query or a time range, you can use:
select * from product where timestamp(add_time) between '2013-01-12 03:23:56' and '2013-01-12 23:23:56'；
or
select * from product where timestamp(add_time) >= '2013-01-12 03:23:56' < '2013-01-12 23:23:56'；
One more, if you want to query in January 2013 added products?
select * from product where date(add_time) between '2013-01-01' and '2013-01-31'
You can also write:
select * from product where Year(add_time) = 2013 and Month(add_time) = 1
These you know your role in the process of comparing the date of issue of mysql date functions, right?
Date_col its value is within the last 30 days:
mysql> SELECT something FROM table
WHERE TO_DAYS(NOW()) - TO_DAYS(date_col) <= 30;
DAYOFWEEK (date)
Returns the date date of the week index (1 = Sunday, 2 = Monday ...... 7 = Saturday). These index values correspond to the ODBC standard.
| mysql> select DAYOFWEEK('1998-02-03');
-> 3 |
WEEKDAY (date)
Returns the date of the week index (0 = Monday, 1 = Tuesday ...... 6 = Sunday).
| mysql> select DAYOFMONTH('1998-02-03');
-> 3 |
DAYOFYEAR (date)
Returns the number of days of date of the year, in the range of 1-366.
| mysql> select DAYOFYEAR('1998-02-03');
-> 34 |
MONTH (date)
Returns the date of the month, the range of 1 to 12.
| mysql> select MONTH('1998-02-03');
-> 2 |
DAYNAME (date)
Returns the name of the date of the week.
| mysql> select DAYNAME("1998-02-05");
-> 'Thursday' |
MONTHNAME (date)
Returns the month name of date.
| mysql> select MONTHNAME("1998-02-05");
-> 'February' |
QUARTER (date)
Returns the quarter of the year in the date range of 1-4.
| mysql> select QUARTER('98-04-01');
-> 2 |
