The SELECT clause projects the columns from one or more base tables that are to be included in the join index definition.
You cannot specify the following options in this SELECT clause:
- TOP n, FULL OUTER JOIN, CROSS JOIN, HAVING, QUALIFY, and SAMPLE
- Any function except RANDOM
- Statistical functions
- Aggregate functions other than SUM and COUNT
- Set operators UNION, EXCEPT/MINUS, INTERSECT, and their derivatives
You cannot specify an EXPAND ON clause in the definition of a join index.
You cannot invoke an SQL UDF anywhere in the definition of a join index.
Certain optional clauses do not become part of the join index definition, for example, output FORMAT and TITLE phrases. You can determine if an option you specify does not become part of the stored join index definition by performing a SHOW JOIN INDEX request to view the DDL for the CREATE JOIN INDEX statement.
For a complete description of the SELECT statement, see SQL Data Manipulation Language, B035-1146.