CASE Expression : Case « Query « SQL Server / T-SQL Tutorial

1. SQL Server / T-SQL Tutorial
2. Query
3. Case

5>
6> CREATE TABLE titles(
7>    title_id       varchar(20),
8>    title          varchar(80)       NOT NULL,
9>    type           char(12)          NOT NULL,
10>    pub_id         char(4)               NULL,
11>    price          money                 NULL,
12>    advance        money                 NULL,
13>    royalty        int                   NULL,
14>    ytd_sales      int                   NULL,
15>    notes          varchar(200)          NULL,
16>    pubdate        datetime          NOT NULL
17> )
18> 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>
3> SELECT  title_id,
4>             CASE SUBSTRING(title_id,1,2)
5>                    WHEN 'BU' THEN 'Business'
6>                    WHEN 'MC' THEN 'Modern Cooking'
7>                    WHEN 'PC' THEN 'Popular Computing'
8>                    WHEN 'PS' THEN 'Psychology'
9>                    WHEN 'TC' THEN 'Traditional Cooking'
10>             END AS BookType
11> FROM titles
12> GO
title_id             BookType
-------------------- -------------------
1                    NULL
2                    NULL
3                    NULL
4                    NULL
5                    NULL
6                    NULL
7                    NULL
8                    NULL

(8 rows affected)
1>
2> drop table titles;
3> GO
1>