All errors › ORA errors
ORA-00918: Column ambiguously defined
What it means
A column name exists in more than one table of the join and the statement does not say which one (in SELECT, WHERE, ORDER BY, or in the inner select of a query wrapped by ROWNUM pagination).
How to fix it
Prefix the column with a table alias (e.alias.col) everywhere it appears. With ANSI JOIN ... USING do not qualify the USING column.
Catch it before it runs
ORA Error Helper
Explains ORA-/PLS- codes inside JetBrains IDEs and DataGrip. PL/SQL Lint
Flags risky PL/SQL patterns while you type. Oracle Plan Reader
Reads execution plans and points at the slow step. PL/SQL in Practice
Kindle book with practical PL/SQL for working developers.
Explains ORA-/PLS- codes inside JetBrains IDEs and DataGrip. PL/SQL Lint
Flags risky PL/SQL patterns while you type. Oracle Plan Reader
Reads execution plans and points at the slow step. PL/SQL in Practice
Kindle book with practical PL/SQL for working developers.
Nearby errors
Updated 2026-11-12.