7 7 Multiple-Column Subqueries Important Legal Notice:  Materials on this lecture are from a book titled “Oracle Education” by Kochhar, Gravina, and Nathan (1999), published by Oracle Corp.  For further information, visit  This presentation must be used for only education purpose for students at Central Washington University which is a member of Oracle Academic Initiatives (OAI) and has used Oracle systems for HRIS & Accounting Systems as a database platform embedded on its PeopleSoft ERP system, since 1999.

Objectives After completing this lesson, you should be able to do the following: Write a multiple-column subquery Describe and explain the behavior of subqueries when null values are retrieved Write a subquery in a FROM clause

Multiple-Column Subqueries Main query MANAGER 10 Subquery SALESMAN30 MANAGER10 CLERK20 Main query compares to Values from a multiple-row and multiple-column subquery MANAGER 10SALESMAN 30 MANAGER 10 CLERK 20

Using Multiple-Column Subqueries Display the order id, product id, and quantity of items in the item table that match both the product id and quantity of an item in order 605. Note: This example applies to a different database from our class database (scott-tiger). SQL> SELECTordid, prodid, qty 2 FROMitem 3 WHERE(prodid, qty) IN ANDordid <> 605; (SELECT prodid, qty FROMitem WHERE ordid = 605)

Using Multiple-Column Subqueries (continued) Display the order number, product number, and quantity of any item in which the product number and quantity match both the product number and quantity of an item in order 605. SQL> SELECTordid, prodid, qty 2 FROMitem 3 WHERE( prodid, qty ) IN ANDordid <> 605; (SELECT prodid, qty FROMitem WHERE ordid = 605

Column Comparisons Pairwise PRODIDQTY Nonpairwise PRODIDQTY

Nonpairwise Comparison Subquery Display the order number, product number, and quantity of any item in which the product number and quantity match any product number and any quantity of an item in Order 605. SQL> SELECTordid, prodid, qty 2 FROMitem 3 WHEREprodid IN ANDqty IN 8 9 ANDordid <> 605; (SELECT prodid, FROMitem WHERE ordid = 605) (SELECT qty FROMitem WHERE ordid = 605)

Nonpairwise Subquery ORDIDPRODIDQTY rows selected.

Null Values in a Subquery SQL> SELECT employee.ename 2 FROM emp employee 3 WHERE employee.empno NOT IN 4 5 no rows selected. (SELECT manager.mgr FROM emp manager);

Using a Subquery in the FROM Clause SQL> SELECTa.ename, a.sal, a.deptno, b.salavg 2 FROM emp a, WHEREa.deptno = b.deptno 6 AND a.sal > b.salavg; (SELECT deptno, avg(sal) salavg FROM emp GROUP BY deptno) b ENAMESALDEPTNOSALAV KING JONES SCOTT rows selected.

Summary A multiple-column subquery returns more than one column. Column comparisons in multiple-column comparisons can be pairwise or nonpairwise. A multiple-column subquery can also be used in the FROM clause of a SELECT statement.