EXISTS and NOT EXISTS in SQL

EXISTS asks whether any matching row exists, and stops at the first one.

SELECT
    c.id,
    c.name
FROM customers AS c
WHERE NOT EXISTS (
    SELECT 1
    FROM orders AS o
    WHERE o.customer_id = c.id
      AND o.placed_at >= '2026-01-01'
)
ORDER BY c.name;

How it works

1. It ignores what the subquery selects, only whether it returns a row.
2. NOT EXISTS is the safe way to say has none of these.
3. Unlike NOT IN, it behaves sanely when NULLs are involved.

Keywords and builtins used here

• AND
• AS
• BY
• EXISTS
• FROM
• NOT
• ORDER
• SELECT
• WHERE
• c

The run, in numbers

Lines

11

Characters to type

162

Tokens

44

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 29 seconds.

Type this snippet

Step 3 of 3 in Subqueries, step 3 of 24 in Analytics & reporting.

← Previous Next →