On Tue, 2021-07-13 at 10:00 -0400, David Gauthier wrote: > I have a column in a table which is a csv of values and I need to make sure each element of the csv = the PK of that same table. This won't work, and it is broken by design. Change your data model to adhere to the first normal form, and the exercise will be simple. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com