对于0到3之间的值，我应该使用哪种数据类型

Question

My field in the database will contain only 3 possible values: 0, 1 and 2. So, I'm wondering what datatype should I use? I found this and it seems that I should use tinyint(1), but that has range from -127 to 126, so am wondering is that my choice or is there actually something better?

Answer 1

tinyint(1) unsigned可能是适合的选择

Answer 2

Not recommended but... I was initially thinking if space is really that big of an issue this may have been worth exploring.

If you can live with NULL, 0, 1 instead of 0,1,2, then boolean/bit may work as well.

However, looks like boolean and tinyint are practically the same. And tinyint has the smallest footprint of all datatypes in mysql. See link .

Answer 3

If you wish to make sure that the number entered is only 0, 1, or 2 then it would be best to add a CHECK constraint to the table.

ALTER TABLE
    tableName
ADD CONSTRAINT 
    checkConstain
CHECK (columnName BETWEEN 0 and 2)

You can see an example of this working on SQL Fiddel