mediumDSA

What is the difference between EXISTS and IN?

Q: What is the difference between EXISTS and IN?

**IN** checks membership against a value list/subquery result; **EXISTS** checks whether a correlated subquery returns any row and can short-circuit. EXISTS is often faster for large or correlated subqueries; IN is fine for small static lists. Beware IN with NULLs causing surprising results.

762 views

Understand the problem

Compare EXISTS and IN.

exists-in

Attempt it yourself

Sketch your approach before reading the solution — that's what interviews test.

Nudge consolestandby

Stuck? Beam a request up — the console returns a conceptual nudge that guides your logic without spoiling the implementation.

Study the solution

IN checks membership against a value list/subquery result; EXISTS checks whether a correlated subquery returns any row and can short-circuit. EXISTS is often faster for large or correlated subqueries; IN is fine for small static lists. Beware IN with NULLs causing surprising results.

Solution ready — 2 min read

Classified // press E to declassify

Run the code

SQLEXISTS vs IN Playground

Join the discussion

Discussion (0)

No responses yet. Be the first to share what you think.

Transmission complete // awaiting log

KEEP THE
STREAK ALIVE.

Dossier 32 of 70 decoded in the SQL track. One more won't hurt.

Back to track

Next up→

Filtered vector search with pgvector — how do you combine WHERE category = 'X' with ORDER BY embedding <=> $1?

Continue