Redgate Simple Talk company blog

Don't use DISTINCT as a "join-fixer"

by Aaron Bertrand red-gate.com published 2023-10-16

Using DISTINCT to fix duplicate rows from a SQL join is a common antipattern. It generates all the duplicates first, then sorts them away - hurting performance. Learn how to rewrite these queries using EXISTS for cleaner, faster SQL Server results.

Points

243

HN comments

170

Submissions

1

Cited by

0 commenters

Databases & DataSoftware Engineering2023

Related posts from the same era

I'm all-in on server-side SQLite

Fly.io Blog20221,353 points565 commentscited by 16 details

GPT in 500 Lines of SQL

Explain Extended20241,111 points76 commentscited by 3 details

Datomic is Free

DDatomic Blog20231,099 points368 commentscited by 5 details

My favourite API is a zipfile on the European Central Bank's website

csvbase Blog20231,024 points265 comments details

Suspicious data pattern in recent Venezuelan election

AAndrew Gelman2024903 points470 comments details

Health insurers just published close to a trillion hospital prices

DoltHub Blog2022901 points526 comments details