The
SQL folder in the Transformation
tree contains a number of transformations that enable you to add SQL
processing to jobs. This chapter is about the Join transformation.
The Join transformation
provides an interface for building the statements and clauses that
constitute queries. The transformation supports the SAS SQL procedure
syntax of
Create table/view <table> as <query
expression> and accommodates up to 256 tables in a
single query. The SELECT statement supports joining the table to itself.
It also supports subqueries; the CASE expression; and WHERE, GROUP
BY, HAVING, and ORDER BY clauses.
The process of building
the SQL query is performed in the
Designer window.
You access this window when you double-click the Join transformation
in a SAS Data Integration Studio job. You use the
Designer window
to create, edit, and review an SQL query. The window contains sections
that are designed to simplify creating the SQL query and configuring
its parts. To return to the SQL job on the
Designer tab
of the
Job Editor window, click
Up on
the toolbar.
The Join transformation
supports the pushdown feature that enables you to process relational
database tables directly on the appropriate relational database server.
For information about pushdown, see
Pushing ELT Job Code Down to a Database.