MySQL IN BETWEEN with no condition

问题

I want to write a SQL query where if the datetime is not been assigned I want to replace a string which can select all date and time.

How Actually it works:

    SELECT * FROM `entry` WHERE `user` like 'TOM' or `user` like 'PHP'
 and `entry_datetime` between '2013-03-13 22:20:18' and '2013-03-13 22:20:26'

My Doubt: If the php do not get the value of the date from and to but I don't want to change the query by deleting the AND condition but I want to replace some thing in between date and time and still the query should run:

    SELECT * FROM `entry` WHERE `user` like 'TOM' or `user` like 'PHP' and 
`entry_datetime` between ' ' and ' '

I tried the following but its not working? can we write a query like this?

    SELECT * FROM `entry` WHERE `user` like 'TOM' or `user` like 'PHP' and 
`entry_datetime` between '%%' and '%%'

I just tries the above like because we use it in LIKE command so I tried that? Any advice will be much helpful.

I dont know the way I am trying is right or wrong but I can't change the Query id the date value is not assigned.

回答1:

You can use MIN and MAX values for datetime data type.

... AND `entry_datetime` BETWEEN '1000-01-01 00:00:00' AND '9999-12-31 23:59:59'

The DATETIME type is used for values that contain both date and time parts. MySQL retrieves and displays DATETIME values in 'YYYY-MM-DD HH:MM:SS' format. The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59'.

回答2:

You could use the IFNULL function

IFNULL(mindate, '1000-01-01');

Problem with this is you would need to know your date range so you could add the minimum and maximum values correctly. This assumes you are passing in or creating a variable called mindate.

回答3:

SELECT  *
FROM    `entry`
WHERE   `user` like 'TOM' or `user` like 'PHP'
and     `entry_datetime`
        between COALESCE('2013-03-13 22:20:18', '1000-01-01 00:00:00')
        and     COALESCE('2013-03-13 22:20:26', '9999-12-31 23:59:59');

SELECT  *
FROM    `entry`
WHERE   `user` like 'TOM' or `user` like 'PHP'
and     `entry_datetime`
        between COALESCE(NULL, '1000-01-01 00:00:00')
        and     COALESCE(NULL, '9999-12-31 23:59:59');

If you pass NULL - optional date values will work as condtions

来源：https://stackoverflow.com/questions/17040898/mysql-in-between-with-no-condition

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