| ERROR | subquery not allowed in this context |
| CAUSE | A subquery was used in an inappropriate context, such as: if (SELECT deptno FROM emp WHERE ... ) = 20 then ... Subqueries are allowed only in SQL statements. |
| ACTION | The same result can be obtained by using a temporary variable, as in: SELECT deptno INTO temp_var FROM emp WHERE ...; IF temp_var = 20 THEN ... |