SQL Server/T-SQL/Transact SQL/Set Variables
Содержание
Assign value returned from a aggregate function to a variable with set statement
<source lang="sql">
5> 6> CREATE TABLE OrderDetails ( 7> OrderID int NOT NULL , 8> ProductID int NOT NULL , 9> UnitPrice money NOT NULL DEFAULT (0), 10> Quantity smallint NOT NULL DEFAULT (1), 11> Discount real NOT NULL DEFAULT (0) 12> ) 13> GO 1> INSERT OrderDetails VALUES(10248,11,14,12,0) 2> INSERT OrderDetails VALUES(10248,42,9.8,10,0) 3> INSERT OrderDetails VALUES(10248,72,34.8,5,0) 4> INSERT OrderDetails VALUES(10249,14,18.6,9,0) 5> INSERT OrderDetails VALUES(10249,51,42.4,40,0) 6> INSERT OrderDetails VALUES(10250,41,7.7,10,0) 7> INSERT OrderDetails VALUES(10250,51,42.4,35,0.15) 8> INSERT OrderDetails VALUES(10250,65,16.8,15,0.15) 9> INSERT OrderDetails VALUES(10251,22,16.8,6,0.05) 10> INSERT OrderDetails VALUES(10251,57,15.6,15,0.05) 11> 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> 2> 3> DECLARE @Test money 4> 5> SET @Test = (SELECT MAX(UnitPrice) FROM OrderDetails) 6> SELECT @Test 7> GO
42.4000
(1 rows affected) 1> 2> drop table OrderDetails; 3> GO
</source>
Assign value to a variable
<source lang="sql">
1> create table employee( 2> ID int, 3> name nvarchar (10), 4> salary int, 5> start_date datetime, 6> city nvarchar (10), 7> region char (1)) 8> GO 1> 2> insert into employee (ID, name, salary, start_date, city, region) 3> values (1, "Jason", 40420, "02/01/94", "New York", "W") 4> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (2, "Robert",14420, "01/02/95", "Vancouver","N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (3, "Celia", 24020, "12/03/96", "Toronto", "W") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (4, "Linda", 40620, "11/04/97", "New York", "N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (5, "David", 80026, "10/05/98", "Vancouver","W") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (6, "James", 70060, "09/06/99", "Toronto", "N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (7, "Alison",90620, "08/07/00", "New York", "W") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (8, "Chris", 26020, "07/08/01", "Vancouver","N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (9, "Mary", 60020, "06/09/02", "Toronto", "W") 3> GO (1 rows affected) 1> 2> select * from employee 3> GO ID name salary start_date city region
---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
(9 rows affected) 1> 2> DECLARE @ValueToUpdate VARCHAR(10) 3> 4> SET @ValueToUpdate = "Mick Bagram" 5> 6> UPDATE Employee 7> SET Name = @ValueToUpdate 8> GO (9 rows affected) 1> 2> select * from employee 3> GO ID name salary start_date city region
---------- ----------- ----------------------- ---------- ------
1 Mick Bagra 40420 1994-02-01 00:00:00.000 New York W
2 Mick Bagra 14420 1995-01-02 00:00:00.000 Vancouver N
3 Mick Bagra 24020 1996-12-03 00:00:00.000 Toronto W
4 Mick Bagra 40620 1997-11-04 00:00:00.000 New York N
5 Mick Bagra 80026 1998-10-05 00:00:00.000 Vancouver W
6 Mick Bagra 70060 1999-09-06 00:00:00.000 Toronto N
7 Mick Bagra 90620 2000-08-07 00:00:00.000 New York W
8 Mick Bagra 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mick Bagra 60020 2002-06-09 00:00:00.000 Toronto W
(9 rows affected) 1> 2> 3> 4> drop table employee 5> GO 1>
</source>
Set value from select statement to a variable
<source lang="sql">
1> create table employee( 2> ID int, 3> name nvarchar (10), 4> salary int, 5> start_date datetime, 6> city nvarchar (10), 7> region char (1)) 8> GO 1> 2> insert into employee (ID, name, salary, start_date, city, region) 3> values (1, "Jason", 40420, "02/01/94", "New York", "W") 4> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (2, "Robert",14420, "01/02/95", "Vancouver","N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (3, "Celia", 24020, "12/03/96", "Toronto", "W") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (4, "Linda", 40620, "11/04/97", "New York", "N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (5, "David", 80026, "10/05/98", "Vancouver","W") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (6, "James", 70060, "09/06/99", "Toronto", "N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (7, "Alison",90620, "08/07/00", "New York", "W") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (8, "Chris", 26020, "07/08/01", "Vancouver","N") 3> GO (1 rows affected) 1> insert into employee (ID, name, salary, start_date, city, region) 2> values (9, "Mary", 60020, "06/09/02", "Toronto", "W") 3> GO (1 rows affected) 1> 2> select * from employee 3> GO ID name salary start_date city region
---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
(9 rows affected) 1> 2> DECLARE @total dec(12,2), @num int 3> 4> SET @total = (SELECT SUM(Salary) FROM Employee) 5> 6> SET @num = (SELECT COUNT(ID) FROM Employee) 7> 8> SELECT @total "Total", 9> @num "Number of employees", 10> @total/@num "Average" 11> GO Total Number of employees Average
------------------- -------------------------
446226.00 9 49580.6666666666666
(1 rows affected) 1> 2> drop table employee 3> GO 1>
</source>
Using SET to Assign Variables
<source lang="sql">
1> 2> -- Using SET to Assign Variables 3> 4> -- Capture the return value for the same function. 5> 6> DECLARE @MyNumber Int, @MyResult Int 7> SET @MyNumber = 144 8> 9> -- Assign the function result to the variable: 10> SET @MyResult = SQRT(@MyNumber) 11> -- Return the variable value 12> SELECT @MyResult 13> GO
12
(1 rows affected) 1>
</source>
