Searched CASE expression looks for the first expression that evaluates to true. : Case « Query « SQL Server / T-SQL Tutorial






If none of the WHEN conditions evaluates to true, the value of the ELSE expression is returned.

9> CREATE TABLE employee(
10>    id          INTEGER NOT NULL PRIMARY KEY,
11>    first_name  VARCHAR(10),
12>    last_name   VARCHAR(10),
13>    salary      DECIMAL(10,2),
14>    start_Date  DATETIME,
15>    region      VARCHAR(10),
16>    city        VARCHAR(20),
17>    managerid   INTEGER
18> );
19> GO
1> INSERT INTO employee VALUES (1, 'Jason' ,  'Martin', 5890,'2005-03-22','North','Vancouver',3);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (2, 'Alison',  'Mathews',4789,'2003-07-21','South','Utown',4);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (3, 'James' ,  'Smith',  6678,'2001-12-01','North','Paris',5);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (4, 'Celia' ,  'Rice',   5567,'2006-03-03','South','London',6);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (5, 'Robert',  'Black',  4467,'2004-07-02','East','Newton',7);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (6, 'Linda' ,  'Green' , 6456,'2002-05-19','East','Calgary',8);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (7, 'David' ,  'Larry',  5345,'2008-03-18','West','New York',9);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (8, 'James' ,  'Cat',    4234,'2007-07-17','West','Regina',9);
2> GO

(1 rows affected)
1> INSERT INTO employee VALUES (9, 'Joan'  ,  'Act',    6123,'2001-04-16','North','Toronto',10);
2> GO

(1 rows affected)
1>
2> select * from employee;
3> GO
id          first_name last_name  salary       start_Date              region     city                 managerid
----------- ---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
          1 Jason      Martin          5890.00 2005-03-22 00:00:00.000 North      Vancouver                      3
          2 Alison     Mathews         4789.00 2003-07-21 00:00:00.000 South      Utown                          4
          3 James      Smith           6678.00 2001-12-01 00:00:00.000 North      Paris                          5
          4 Celia      Rice            5567.00 2006-03-03 00:00:00.000 South      London                         6
          5 Robert     Black           4467.00 2004-07-02 00:00:00.000 East       Newton                         7
          6 Linda      Green           6456.00 2002-05-19 00:00:00.000 East       Calgary                        8
          7 David      Larry           5345.00 2008-03-18 00:00:00.000 West       New York                       9
          8 James      Cat             4234.00 2007-07-17 00:00:00.000 West       Regina                         9
          9 Joan       Act             6123.00 2001-04-16 00:00:00.000 North      Toronto                       10

(9 rows affected)
1>
2>
3>
4>       SELECT first_name,
5>         CASE
6>          WHEN salary > 0 AND salary < 100000 THEN 1
7>          WHEN salary >= 100000 AND salary < 200000 THEN 2
8>          WHEN salary >= 200000 AND salary < 300000 THEN 3
9>          ELSE 4
10>         END budget_weight
11>        FROM Employee
12> GO
first_name budget_weight
---------- -------------
Jason                  1
Alison                 1
James                  1
Celia                  1
Robert                 1
Linda                  1
David                  1
James                  1
Joan                   1

(9 rows affected)
1>
2>
3> drop table employee;
4> GO








1.23.Case
1.23.1.The syntax pattern for case
1.23.2.The syntax of the searched CASE function
1.23.3.A Simple CASE
1.23.4.CASE Expression
1.23.5.Automatic Code Generation for CASE Expressions
1.23.6.Summarizing Data Using the CASE Expression
1.23.7.Using a CASE expression to sum sales by weekday.
1.23.8.Using the CASE Expression with Complex Conditions
1.23.9.Summarizing Data Using the Searched CASE Expression
1.23.10.A SELECT statement that uses a simple CASE function
1.23.11.A SELECT statement that uses a searchable CASE function
1.23.12.Searched CASE expression looks for the first expression that evaluates to true.
1.23.13.Update statement based on case condition
1.23.14.Case when else
1.23.15.Alias for case statement
1.23.16.Use two case statements in one select statement
1.23.17.Case then with query
1.23.18.Case with range
1.23.19.Doing a calculation in a Searched CASE