How to compare the size of dates in Mysql

Xiaobian to share with you how to compare the size of the date in Mysql, I believe most people still do not know how to, so share this article for your reference, I hope you have a lot of harvest after reading this article, let's go to understand it together!

If there is a table product with a field add_time, and its data type is datetime, someone might write sql like this:

code is as follows

select * from product where add_time = '2013-01-12'

For this statement, if you store the format YY-mm-dd is like this, then OK, if you store the format is: 2013-01-12 23:23:56 This format you are tragic, this is the part you can use DATE() function to return the date, so this sql should be processed as follows:

code is as follows

select * from product where Date(add_time) = '2013-01-12'

Another one, if you want to inquire about products added in January 2013?

code is as follows

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

Do you know what mysql's date function does to your date comparison problem?

The value of date_col is within the last 30 days:

code is as follows

mysql> SELECT something FROM table WHERE TO_DAYS(NOW()) - TO_DAYS(date_col) select DAYOFWEEK('1998-02-03'); -> 3 WEEKDAY(date)

Returns the week index of date (0= Monday, 1= Tuesday, ……6= Sunday).

code is as follows

mysql> select WEEKDAY('1997-10-04 22:23:00'); -> 5 mysql> select WEEKDAY('1997-11-05'); -> 2 DAYOFMONTH(date)

Returns the date of the month in the range 1 to 31.

code is as follows

mysql> select DAYOFMONTH('1998-02-03'); -> 3 DAYOFYEAR(date)

Returns the number of days in a year, in the range 1 to 366.

code is as follows

mysql> select DAYOFYEAR('1998-02-03'); -> 34 MONTH(date)

Returns the month of date, in the range 1 to 12.

code is as follows

mysql> select MONTH('1998-02-03'); -> 2 DAYNAME(date)

Returns the week name of date.

code is as follows

mysql> select DAYNAME("1998-02-05"); -> 'Thursday' MONTHNAME(date)

Returns the month name of date.

code is as follows

mysql> select MONTHNAME("1998-02-05"); -> 'February' QUARTER(date)

Returns the quarter of the year in the range 1 to 4.

code is as follows

mysql> select QUARTER ('98 -04- 01'); -> 2 The above is all the content of this article, thank you for reading! I believe that everyone has a certain understanding, hope to share the content to help everyone, if you still want to learn more knowledge, welcome to pay attention to the industry information channel!