Question

I’ve got to do research in a database system where foreign keys for an 1:n relationship are stored as comma separated list in a single column. I want to do a query which prints out every row from table A where the primary key is found in a certain column of table B, but I just don’t get how to do it. The database used is oracle 10, if that helps.

Answer 1

You want to use the INSTR function.

Select A.*
FROM Foo A
Where A.ID IN 
  (SELECT A.ID FROM Bar B 
   Where INSTR(','||B.ConcatKeyField||',', ','||A.ID||`,', 1, 1) > 0)