Using EXEC () to Execute a Dynamic TOP n Query : EXEC « Transact SQL « SQL Server / T-SQL Tutorial






3>
4> CREATE TABLE employee(
5>    id          INTEGER NOT NULL PRIMARY KEY,
6>    first_name  VARCHAR(10),
7>    last_name   VARCHAR(10),
8>    salary      DECIMAL(10,2),
9>    start_Date  DATETIME,
10>    region      VARCHAR(10),
11>    city        VARCHAR(20),
12>    managerid   INTEGER
13> );
14> 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> DECLARE
5>   @ExecStr varchar (2000),
6>   @N       int
7> SELECT
8>   @N = 5
9> SELECT
10>   @ExecStr = 'SELECT TOP ' + STR (@N, 2) + ' * '
11>            + 'FROM Employee ORDER BY ID DESC'
12> EXEC (@ExecStr)
13>
14>
15>
16> drop table employee;
17> GO
id          first_name last_name  salary       start_Date              region     city                 managerid
----------- ---------- ---------- ------------ ----------------------- ---------- -------------------- -----------
          9 Joan       Act             6123.00 2001-04-16 00:00:00.000 North      Toronto                       10
          8 James      Cat             4234.00 2007-07-17 00:00:00.000 West       Regina                         9
          7 David      Larry           5345.00 2008-03-18 00:00:00.000 West       New York                       9
          6 Linda      Green           6456.00 2002-05-19 00:00:00.000 East       Calgary                        8
          5 Robert     Black           4467.00 2004-07-02 00:00:00.000 East       Newton                         7

(5 rows affected)








20.19.EXEC
20.19.1.The syntax of the EXEC statement
20.19.2.EXECUTE AS
20.19.3.Dynamic Selects
20.19.4.A stored procedure with dynamic execution by using EXEC
20.19.5.Sending Variable Information to an EXEC() Call
20.19.6.Switch database in EXEC
20.19.7.Statement Limit
20.19.8.Parse exception in another level of scope: Exception in EXEC
20.19.9.Execute a dynamic statement and return the result with OUTPUT
20.19.10.Use more than one sql statement in EXEC
20.19.11.Insert into with EXEC
20.19.12.Using EXEC () to Execute a Dynamic TOP n Query