ORA error

ORA-01427

ORA-01427: single-row subquery returns more than one row

Quick fix

Cause: A subquery used with a single-row operator (=, <, >, or as a scalar value in the SELECT list) returned several rows.
Fix: Use IN / ANY / EXISTS instead of =, or make the subquery return one row (an aggregate such as MAX, a tighter WHERE, or FETCH FIRST 1 ROW ONLY) — whichever matches what the query is meant to do.

ORA-01427: single-row subquery returns more than one row – Use IN instead of = for multi-row subqueries.

Database