Using a Condition in the WHERE Clause
You can use these simple conditions or comparisons in the WHERE
clause:
- Relational-operator condition
- IN or BETWEEN . . . AND
- IS NULL or IS NOT NULL
- LIKE or MATCHES
You also can use a SELECT statement within the WHERE clause; this
is called a subquery. The following WHERE clause operators
are valid in a subquery:
- IN or EXISTS
- ALL, ANY, or SOME
For more information, see Condition.
In the WHERE clause, an aggregate function is not valid unless it is part of a subquery or is on a correlated column originating from a parent query, and the WHERE clause is in a subquery within a HAVING clause.