Mega Code Archive
A common use for EXISTS is to answer a query such as Show me the titles for which no stores have sales
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7> CREATE TABLE sales(
8> stor_id char(4) NOT NULL,
9> ord_num varchar(20) NOT NULL,
10> ord_date datetime NOT NULL,
11> qty smallint NOT NULL,
12> payterms varchar(12) NOT NULL,
13> title_id varchar(80)
14> )
15> GO
1> insert sales values('1', 'QA7442.3', '09/13/94', 75, 'ON Billing','1')
2> insert sales values('2', 'D4482', '09/14/94', 10, 'Net 60', '1')
3> insert sales values('3', 'N914008', '09/14/94', 20, 'Net 30', '2')
4> insert sales values('4', 'N914014', '09/14/94', 25, 'Net 30', '3')
5> insert sales values('5', '423LL922', '09/14/94', 15, 'ON Billing','3')
6> insert sales values('6', '423LL930', '09/14/94', 10, 'ON Billing','2')
7> GO
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
1>
2>
3> CREATE TABLE titles(
4> title_id varchar(20),
5> title varchar(80) NOT NULL,
6> type char(12) NOT NULL,
7> pub_id char(4) NULL,
8> price money NULL,
9> advance money NULL,
10> royalty int NULL,
11> ytd_sales int NULL,
12> notes varchar(200) NULL,
13> pubdate datetime NOT NULL
14> )
15> GO
1>
2> insert titles values ('1', 'Secrets', 'popular_comp', '1389', $20.00, $8000.00, 10, 4095,'Note 1','06/12/94')
3> insert titles values ('2', 'The', 'business', '1389', $19.99, $5000.00, 10, 4095,'Note 2','06/12/91')
4> insert titles values ('3', 'Emotional', 'psychology', '0736', $7.99, $4000.00, 10, 3336,'Note 3','06/12/91')
5> insert titles values ('4', 'Prolonged', 'psychology', '0736', $19.99, $2000.00, 10, 4072,'Note 4','06/12/91')
6> insert titles values ('5', 'With', 'business', '1389', $11.95, $5000.00, 10, 3876,'Note 5','06/09/91')
7> insert titles values ('6', 'Valley', 'mod_cook', '0877', $19.99, $0.00, 12, 2032,'Note 6','06/09/91')
8> insert titles values ('7', 'Any?', 'trad_cook', '0877', $14.99, $8000.00, 10, 4095,'Note 7','06/12/91')
9> insert titles values ('8', 'Fifty', 'trad_cook', '0877', $11.95, $4000.00, 14, 1509,'Note 8','06/12/91')
10> GO
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
1>
2> SELECT T.title_id, title FROM titles T
3> WHERE NOT EXISTS
4> (SELECT 1
5> FROM sales S
6> WHERE T.title_id=S.title_id )
7> GO
title_id title
-------------------- --------------------------------------------------------------------------------
4 Prolonged
5 With
6 Valley
7 Any?
8 Fifty
(5 rows affected)
1>
2> drop table titles;
3> drop table sales;
4> GO
1>
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