The syntax of a subquery that uses the EXISTS operator : Exists « Query « SQL Server / T-SQL Tutorial






WHERE [NOT] EXISTS (subquery)

use the EXISTS operator to test that one or more rows are returned by the subquery.
When you use the EXISTS operator with a subquery, the subquery doesn't actually return any rows.
Instead, it returns an indication of whether any rows meet the specified condition.
11>
12>
13>
14> create table Billings (
15>     BankerID           INTEGER,
16>     BillingNumber      INTEGER,
17>     BillingDate        datetime,
18>     BillingTotal       INTEGER,
19>     TermsID            INTEGER,
20>     BillingDueDate     datetime ,
21>     PaymentTotal       INTEGER,
22>     CreditTotal        INTEGER
23>
24> );
25> GO
1>
2> INSERT INTO Billings VALUES (1, 1, '2005-01-22', 165, 1,'2005-04-22',123,321);
3> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (2, 2, '2001-02-21', 165, 1,'2002-02-22',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (3, 3, '2003-05-02', 165, 1,'2005-04-12',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (4, 4, '1999-03-12', 165, 1,'2005-04-18',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (5, 5, '2000-04-23', 165, 1,'2005-04-17',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (6, 6, '2001-06-14', 165, 1,'2005-04-18',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (7, 7, '2002-07-15', 165, 1,'2005-04-19',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (8, 8, '2003-08-16', 165, 1,'2005-04-20',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (9, 9, '2004-09-17', 165, 1,'2005-04-21',123,321);
2> GO

(1 rows affected)
1> INSERT INTO Billings VALUES (0, 0, '2005-10-18', 165, 1,'2005-04-22',123,321);
2> GO

(1 rows affected)
1>
2>
3>
4> create table Bankers(
5>    BankerID             Integer,
6>    BankerName           VARCHAR(20),
7>    BankerContactLName   VARCHAR(20),
8>    BankerContactFName   VARCHAR(20),
9>    BankerCity           VARCHAR(20),
10>    BankerState          VARCHAR(20),
11>    BankerZipCode        VARCHAR(20),
12>    BankerPhone          VARCHAR(20)
13> )
14> GO
1>
2> insert into Bankers values (1, 'ABC Inc.','Joe','Smith','Vancouver','BC','11111','111-111-1111');
3> GO

(1 rows affected)
1> insert into Bankers values (2, 'DEF Inc.','Red','Rice', 'New York', 'DE','22222','222-222-2222');
2> GO

(1 rows affected)
1> insert into Bankers values (3, 'HJI Inc.','Kit','Cat',  'Paris',    'CA','33333','333-333-3333');
2> GO

(1 rows affected)
1> insert into Bankers values (4, 'QWE Inc.','Git','Black','Regina',   'ER','44444','444-444-4444');
2> GO

(1 rows affected)
1> insert into Bankers values (5, 'RTY Inc.','Wil','Lee',  'Toronto',  'YU','55555','555-555-5555');
2> GO

(1 rows affected)
1> insert into Bankers values (6, 'YUI Inc.','Ted','Larry','Calgary',  'TY','66666','666-666-6666');
2> GO

(1 rows affected)
1> insert into Bankers values (7, 'OIP Inc.','Yam','Act',  'San Franc','FG','77777','777-777-7777');
2> GO

(1 rows affected)
1> insert into Bankers values (8, 'SAD Inc.','Hit','Eat',  'Orland',   'PO','88888','888-888-8888');
2> GO

(1 rows affected)
1> insert into Bankers values (9, 'DFG Inc.','Sad','Lee',  'Wisler',   'PL','99999','999-999-9999');
2> GO

(1 rows affected)
1> insert into Bankers values (0, 'GHJ Inc.','Bit','Lee',  'Ticker',   'MN','00000','000-000-0000');
2> GO

(1 rows affected)
1>
2>
3>
4> SELECT BankerID, BankerName, BankerState
5> FROM Bankers
6> WHERE NOT EXISTS
7>     (SELECT *
8>     FROM Billings
9>     WHERE Billings.BankerID = Bankers.BankerID)
10> GO
BankerID    BankerName           BankerState
----------- -------------------- --------------------

(0 rows affected)
1>
2> drop table Billings;
3> drop table Bankers;
4> GO








1.10.Exists
1.10.1.The syntax of a subquery that uses the EXISTS operator
1.10.2.EXISTS() returns a row in the outer query when any records are returned by a subquery.
1.10.3.A simple subquery using the EXISTS clause.
1.10.4.NOT EXISTS with correlated subquery
1.10.5.IF EXISTS
1.10.6.A common use for EXISTS is to answer a query such as Show me the titles for which no stores have sales.