Be careful with blanket CTE recommendations. They tend to deoptimize with writes... | Hacker News

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		eyelidlessness on Aug 30, 2021 \| parent \| context \| favorite \| on: Challenges students face when learning to work wit... Be careful with blanket CTE recommendations. They tend to deoptimize with writes in really surprising ways. If you’re just reading data, they’re great.

hobs on Aug 30, 2021 [–]

I would still say they are not great as most engines just... write your sql out, instead of saving/memoizing anything.

eyelidlessness on Aug 30, 2021 | [–]

All of my experience here is with Postgres, where (in recent versions) read-only CTEs are basically temporary views with all the built in optimizations that come from that.

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