Databases · Middle · Question 5 of 75

What is a partial index?

CREATE INDEX ON orders (created_at) WHERE status = 'pending';

1An index that covers only part of each value
✓Correct answer: An index on only the rows matching a condition, which makes it smaller and cheaper to maintain
3An index that is built in the background

Explanation

It's great when queries always filter on a rare value. A partial unique index can also enforce rules like 'one active subscription per user'.

Further reading

PostgreSQL: Partial indexes ↗

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