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66
votes
4answers
111k views

Best practice between using LEFT JOIN or NOT EXISTS

Is there a best practice between using a LEFT JOIN or a NOT EXISTS format? What is benefit to using one over the other? If none, which should be preferred? SELECT * FROM tableA A LEFT JOIN tableB B ...
34
votes
2answers
3k views

IF EXISTS taking longer than embedded select statement

When I run the following code it takes 22.5 minutes and does 106million reads. However, if I run just the inner select statement by itself it only takes 15 seconds and does 264k reads. As a side note, ...
11
votes
1answer
1k views

Does the SQL Spec require a GROUP BY in EXISTS ()

Microsoft currently permits this syntax. SELECT * FROM ( VALUES (1) ) AS g(x) WHERE EXISTS ( SELECT * FROM ( VALUES (1),(1) ) AS t(x) WHERE g.x = t.x HAVING count(*) > 1 ); Notice ...
2
votes
1answer
575 views

Full text search on two tsvector columns

I'm trying to do a full text search across two columns of two separate tables in PostgreSQL 9.4.2. The tables and columns are: article.article_title keyword.keyword Where there is a many-to-many ...
3
votes
1answer
5k views

pg_restore ERROR: “Relation does not exist” and creating new database

I have made a backup of my specific tables that I want to restore into a new database using: call pg_dump -Fc -h server -d database -U user -p password -v -f dump.sql -t public.table1 -t public....
0
votes
1answer
3k views

How can I create a bool column for a view based on the result of a statement?

I'm using PostgreSQL as my database. CREATE TABLE groups ( id SERIAL NOT NULL, name TEXT NOT NULL, PRIMARY KEY (id), UNIQUE (name) ); CREATE TABLE users ( id ...