On 13.01.22 13:43, Alvaro Herrera wrote:
> Apologies, there was a merge failure and I failed to notice. Here's the
> correct patch.
I looked through this a bit. I wonder why there is a check for
"unreachable WHEN clause". I don't see this in the SQL standard.
On the other hand, there is a requirement in the SQL standard that the
correlation names exposed by the source and target tables are different.
This is currently caught indirectly with a message like
ERROR: table name "t" specified more than once
because of the way everything ends up in a join tree. But that seems
implementation-dependent, and a more explicit check might be better.