The SELECT statement in the preceding example is supported by multiple versions of Oracle. However, Oracle 9i also supports the new ANSI 1999 SQL standard, and the SELECT statement can be modified as follows according to this new standard:
SELECT i.first_name' 'i.last_name, COUNT(*) INTO v_name, v_total FROM instructor i JOIN section s ON (i.instructor_id = s.instructor_id) WHERE i.instructor_id = 102 GROUP BY i.first_name' 'i.last_name;
Notice, the FROM clause contains only one table, INSTRUCTOR. Following the FROM clause is the JOIN clause that lists the second table, SECTION. Next, the ON clause lists the join condition between the two tables
i.instructor_id = s.instructor_id
which has been moved from the WHERE clause.