On Wednesday, June 8, 2016, Ed Felstein <efelst...@gmail.com> wrote: > Hello, > First time poster here. Bear with me. > Using PostgreSQL 9.5 > I have a situation where I have a LIKE and a NOT LIKE in the same query to > identify strings in a varchar field. Since I am using wildcards, I have > created a GIN index on the field in question, which makes LIKE '%xxxx%' > searches run very fast. The problem is the NOT LIKE phrases, which (as > would be expected) force a sequential scan. Being that we're talking about > millions of records, this is not desirable. > Here's the question... > Is there a way, *using a single query*, to emulate the process of running > the LIKE part first, then running the NOT LIKE just on those results? I > can accomplish this in a multi-step process by separating the single query > into two queries, populating a temporary table with the results of the > LIKEs, then running the NOT LIKEs on the temporary table. For various > reasons, this is not the ideal solution for me. > Or is there another approach that would accomplish the same thing with the > same level of performance? >
Try AND...where col like '' and col not like '' Or a CTE (with) With likeqry as ( select where like ) Select from likeqry where not like (sorry for brevity but not at a pc) David J.
