| ERROR | subquery in an IN or NOT IN clause must contain exactly one column |
| CAUSE | An invalid expression such as X IN (SELECT A,B ...) was used. When a [NOT]IN clause is used with a subquery, it does not test for set membership. The number of expressions in the [NOT]IN clause and the subquery select list must match. So, in the example above, the subquery must specify at most one column. |
| ACTION | Change the subquery to select only one column. |