EC
1994
MariaDBERRORNotableQueryHIGH confidence

Every derived table must have its own alias

Production Risk

Low — query is rejected; no data is modified.

What this means

A subquery used as a derived table in the FROM clause was not given an alias. MySQL requires every derived table (inline view) in a FROM clause to be aliased.

Why it happens
  1. 1Subquery in FROM clause without an AS alias.
  2. 2Missing alias after a parenthesised subquery used as a table.
How to reproduce
trigger — this will error
trigger — this will error
SELECT * FROM (SELECT id, name FROM users);

expected output

ERROR 1994 (42000): Every derived table must have its own alias.

Fix

Add an alias to the derived table

Add an alias to the derived table
SELECT * FROM (SELECT id, name FROM users) AS u;

Why this works

The alias gives the derived table a name so the outer query can reference it.

What not to do

✕

Sources
Official documentation ↗

MySQL 8.0 — 1994 ER_DERIVED_MUST_HAVE_ALIAS

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