从联接表中选择多行

Question

I have a table A with a field X that contains a value list like 1,2,3 Then there is a second Table B with a field uid. If AX contains 1,2,3 i want to get the rows from table B where uid is 1 or 2 or 3.

I tried a Join like:

SELECT b.value FROM A a JOIN B b ON b.uid IN ( a.X )

This kinda works but i only get 1 Result in b.value of course. How can I get all the Results? I know i could just use a second Query, but it is possible to get this in one?

(I know it is not nice to use such a structure and one should use nn tables, but this is given by the used System)

Answer 1

As you state in your question this is not a good design. I think the following should work (albeit not with good performance)

SELECT b.value 
FROM A a 
JOIN B b ON  CONCAT(',',a.X,',') LIKE CONCAT('%,',b.uid,',%')