Cause: The number of expressions in an
IN clause did not equal the number of expressions in a corresponding subquery
select list. For example, the following statement is invalid because the IN
clause contains two expressions, but the subquery select list contains just
one: … WHERE (ename, sal) IN (SELECT sal FROM emp);
Action: Check the number of expressions
in each set, then revise the statement to make the numbers
equal.

Relared Errors:
PLS-00327:
string is not in SQL scope here
PLS-00328: A
subprogram body must be defined for the forward declaration of
string.
PLS-00329:
schema-level type has illegal reference to string
PLS-00330:
invalid use of type name or subtype name
PLS-00331:
illegal reference to string
PLS-00332:
string is not a valid prefix for a qualified name
PLS-00333:
string must match an object-table alias in this
context
PLS-00334:
string matches table or view without an alias
PLS-00335: a
package name conflicts with an existing object
PLS-00336:
non-object-table string illegal in this context