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Exclusion constraint with negated operator? - Mailing list pgsql-general

From	Torsten Förtsch
Subject	Exclusion constraint with negated operator?
Date	June 13, 2023 21:11:01
Msg-id	CAKkG4_=4Wo43KfFNE1i_91p+xJnGry_WM8fngH8Tv=F5wBD=wA@mail.gmail.com Whole thread Raw
Responses	Re: Exclusion constraint with negated operator?
List	pgsql-general

Hi,

I wanted to create an exclusion constraint like

EXCLUDE (c1 WITH =, c2 with <>)

This gives an error:

operator <>(integer,integer) is not a member of operator family "integer_ops"

I can resolve that by using gist and the btree_gist extension.

My question is can I somehow express something like

EXCLUDE (c1 WITH =, c2 with NOT =)

It seems that's not possible at the moment. But is there any obstacle in principle or is it just not implemented?

We have a ton of overlap operators (geometric, ranges, arrays) but none for the opposite. Sometimes that's useful for exclusion constraints.

Thanks,

Torsten

From: "David G. Johnston"
Date: 13 June 2023, 21:07:50
Subject: Re: Reproducing incorrect order with order by in a subquery

From: "Patrick O'Toole"
Date: 13 June 2023, 22:24:51
Subject: Helping planner to chose sequential scan when it improves performance