MySQL：返回“0”和“1”而不是“假”和“真”

Question

I need to return true or false rather than 1 & 0 , using following query:

select if(u.id is null,false,true) status
from user u
limit 10

the above query returns status with value 0 or 1 rather than true and false ,

Is there any way to fix this?

Answer 1

If you want, you can return the values as strings :

SELECT IF(u.id IS NULL, 'false', 'true') as status
FROM user u
LIMIT 10

Answer 2

TRUE/FALSE is equivalent to 1/0. It's just a matter of how your front end displays it.

If you need to return the strings "true" and "false" (which I don't suggest - handle that in the display) then you'll have to account for that as well:

IF(IF(u.id ISNULL,false,true) = 1, 'TRUE', 'FALSE')

Answer 3

MySQL has no boolean datatype, so you need to stick with 0 and 1 on the MySQL side:

select if(u.id is null, 0, 1) status_int
from user u
limit 10

If you prefer a boolean over 0/1 in PHP, you can cast it like this:

$status = (bool) $status_int;

Answer 4

IF()

You are missing single quotes.

select if(u.id is null,'false','true') status
from user u
limit 10;

Answer 5

I just had a similar issue in lua. For some reason if the table column type is "tinyint" and you call 1 or 0 it will return as true and false. If you change the column type to "int" it will call and return in lua as 1 and 0.

Old post but I hope this helps someone!