Question

I am trying to select a table based on the value of the input in another table. lets say

SELECT tale0.*,class.*,hamburger.* 
FROM 
    CASE tale0.id=1 
        THEN class 
    END 
        CASE tale0.id=2 
            THEN hamburger

is this the way to go or is there a different method?

Answer 1

No, you can’t use a CASE statement in the FROM clause. You will need to join in both tables, then pull the field from the relevant table based on the value:

SELECT
    tale0.*,
    CASE WHEN tale0.id = 1 THEN class.Column1 ELSE hamburger.Column1 END as Column1,
    CASE WHEN tale0.id = 1 THEN class.Column2 ELSE hamburger.Column2 END as Column2,
    ...
FROM
    table0, class, hamburger
-- include join conditions