Vol. I · A Postgres HandbookTwelve chapters · · 756 queries

The Query & the Schema

A reading-room reference for writing PostgreSQL by hand — selects to window functions, with the schema in plain view.

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Chapters · WHERE & Filtering · Query 011 / 030
IntermediateWHERE & Filtering

Find products with NULL cost (cost unknown)

The query

SQL
SELECT product_id, name, price
FROM products
WHERE cost IS NULL;
Tested against PostgreSQL 16

Note

“NULL means "unknown" or "not applicable". Always use IS NULL, never = NULL.

Tables referenced

  • products6 cols

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The Query & the Schema

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Compiled for Postgres 16 · MMXXVI