Because each row counted is already unique, DISTINCT will have no impact.
5>
6>
7> CREATE TABLE CD (
8> CD_ID integer NOT NULL PRIMARY KEY,
9> CD_Title varchar(40),
10> Composer_ID integer NOT NULL,
11> Classif_ID integer NOT NULL,
12> SalesPrice money,
13> AverageCost money)
14> GO
1> INSERT into CD VALUES(2000,"John",100,1,16.99,6.99)
2> INSERT into CD VALUES(2001,"Chicago 16",107,1,14.99,5.99)
3> INSERT into CD VALUES(2002,"Chicago 17",107,1,14.99,5.99)
4> INSERT into CD VALUES(2003,"Chicago 18",107,1,14.99,5.99)
5> INSERT into CD VALUES(2004,"Greatest Hits",107,1,16.99,7.99)
6> INSERT into CD VALUES(2005,"Midnight",101,3,14.99,5.99)
7> INSERT into CD VALUES(2006,"Mode",115,3,14.99,5.99)
8> INSERT into CD VALUES(2007,"Ultra",115,3,15.99,5.99)
9> INSERT into CD VALUES(2008,"Mindcrime",102,4,14.99,5.99)
10> INSERT into CD VALUES(2009,"Empire",102,4,14.99,5.99)
11> INSERT into CD VALUES(2010,"Land",102,4,12.99,4.99)
12> INSERT into CD VALUES(2011,"Night",103,4,11.99,3.99)
13> INSERT into CD VALUES(2012,"Pyromania",103,4,14.99,5.99)
14> INSERT into CD VALUES(2013,"Hysteria",103,4,14.99,5.99)
15> INSERT into CD VALUES(2014,"Hits",103,4,13.99,4.99)
16> INSERT into CD VALUES(2015,"Hits 2",104,2,15.99,6.99)
17> INSERT into CD VALUES(2016,"Greatest",105,2,14.99,5.99)
18> INSERT into CD VALUES(2017,"Hits 3",106,1,13.99,5.99)
19> INSERT into CD VALUES(2018,"Deep",108,1,12.99,2.99)
20> INSERT into CD VALUES(2019,"Turning",109,1,14.99,5.99)
21> INSERT into CD VALUES(2020,"TheHits",109,1,16.99,7.99)
22> INSERT into CD VALUES(2021,"Cars",110,1,9.99,3.99)
23> INSERT into CD VALUES(2022,"Anthology",110,1,25.99,11.99)
24> INSERT into CD VALUES(2023,"City",110,1,14.99,5.99)
25> INSERT into CD VALUES(2024,"Rick",111,1,11.99,2.99)
26> INSERT into CD VALUES(2025,"Live",112,1,19.99,8.99)
27> INSERT into CD VALUES(2026,"Pat",113,1,16.99,6.99)
28> INSERT into CD VALUES(2027,"Big",114,1,14.99,5.99)
29> INSERT into CD VALUES(2028,"Hurting",114,1,11.99,3.99)
30> INSERT into CD VALUES(2029,"Vol 1",116,1,9.99,2.99)
31> INSERT into CD VALUES(2030,"Vol 2",116,1,9.99,2.99)
32> 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 rows affected)
(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 rows affected)
(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 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
1>
2>
3> SELECT DISTINCT COUNT(Classif_ID) from CD
4> GO
-----------
31
(1 rows affected)
1>
2> drop table CD;
3> GO