Mysql: how to add a virtual column before UNION

Question

I want to add a virtual column 'enabled' = 1 for all the result from the first union of my statement, and the 'enabled' = 0 for the next union. This is the statement I have so far...

SELECT p.*
FROM member_permissions mp
JOIN permissions p ON p.permission_id = mp.permission_id
WHERE member_id = 1
UNION
SELECT pgp
FROM member_permissions mp
JOIN permission_link pl ON pl.permission_group_id = mp.permission_group_id
JOIN permissions pgp ON pgp.permission_id = pl.permission_id
WHERE member_id = 1
UNION        // this will have enabled = 0 //    
SELECT *
FROM permissions        

Answer 1

Just specify the new column as the source:

select column1, column2, ..., 1 as enabled
from ....
union
select column1, column2, ..., 0 as enabled
from ....

Just a note, you must use the same number of columns with the same data types when using union.