[blendo]

Do you mean “incorrect” in the sense that comparing a customer_id to an order_id is semantic nonsense?

I agree, and I do wish SQL had stronger typing so the parser could warn you before your query silently runs off the rails. For example, in Oracle, I believe the following is legal, but I wish it wasn’t:

   select * 
   from my tab 
   where 1 = ‘1’