Using Clause In Sql

The Using Clause specifies which columns to test for equality when two tables are joined.it can be used insted of an on clause in the join operation that have an explicit join clause.


Syntax:-
Using(simple-column name[,simple column name]*)
The Columns listed in the using clause mumst be present in both of two being joined.The USING clause will be  transformed to an ON clause for equality between the

named columns in two tables.



For Example :- SQL> SELECT l.city, d.department_name
  2  FROM   locations l JOIN departments d USING (location_id)
  3  WHERE  location_id = 1400;

CITY                           DEPARTMENT_NAME
------------------------------ ------------------------------
Southlake                      IT