SQL Server/T-SQL/Store Procedure Function/Create Function — различия между версиями

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Текущая версия на 10:21, 26 мая 2010

Define function to get last name

14>
15> CREATE FUNCTION fnName (@Name VarChar(100))
16>   RETURNS VarChar(100)
17> AS
18>   BEGIN
19>      DECLARE @CommaPosition Int, @LastName varchar(100)
20>      SET @CommaPosition = 6
21>      SET @LastName = SUBSTRING(@Name, 1, @CommaPosition)
22>      RETURN @LastName
23>   END
24> GO
Msg 2714, Level 16, State 3, Server sqle\SQLEXPRESS, Procedure fnName, Line 22
There is already an object named "fnName" in the database.
1>
2> SELECT dbo.fnName("Washington, George")
3> GO
------------------------------------------------------------------------------------------
Washin
(1 rows affected)
1>
2> drop function fnName
3> GO



Define user function and use it in select statement

1>
2> CREATE FUNCTION dbo.ufnIsOdd (@n int)
3> RETURNS bit
4> AS
5> BEGIN
6>     RETURN (@n % 2)
7> END
8> GO
1>
2> DECLARE @numb int
3> SET @numb = 6
4> SELECT @numb "Number", dbo.ufnIsOdd (@numb) "Is_odd = 1"
5> SET @numb = 7
6> SELECT @numb "Number", dbo.ufnIsOdd (@numb) "Is_odd = 1"
7>
8> GO
Number      Is_odd = 1
----------- ----------
          6          0
(1 rows affected)
Number      Is_odd = 1
----------- ----------
          7          1
(1 rows affected)
1>



Inline Table-Valued Functions

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> -- Inline Table-Valued Functions
3>
4> CREATE FUNCTION myProc(@ID Int)
5>   RETURNS Table
6> AS
7>   RETURN
8>   (
9>     SELECT ID, Name, Salary FROM Employee
10>     WHERE ID = @ID
11> )
12> GO
1> SELECT * FROM myProc(1)
2> GO
ID          Name       Salary
----------- ---------- -----------
          1 Jason            40420
(1 rows affected)
1>
2> drop table employee
3> GO
1>



Multi-Statement Table-Valued Functions

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> -- Multi-Statement Table-Valued Functions
3>
4> CREATE FUNCTION myProc (@ID Int)
5>   RETURNS @EmployeeList Table
6>     (  ID     Int
7>      , Name   nVarChar(50)
8>      , Salary Money
9>     )
10> AS
11>   BEGIN
12>     IF @ID IS NULL
13>       BEGIN
14>         INSERT INTO @EmployeeList (ID, Name, Salary)
15>         SELECT ID, Name, Salary
16>         FROM Employee
17>       END
18>     ELSE
19>       BEGIN
20>         INSERT INTO @EmployeeList (ID, Name, Salary)
21>         SELECT ID, Name, Salary
22>         FROM Employee
23>         WHERE ID = @ID
24>       END
25>     RETURN
26>   END
27> GO
1>
2> select * from myProc(1)
3> GO
ID          Name                                               Salary
----------- -------------------------------------------------- ---------------------
          1 Jason                                                         40420.0000
(1 rows affected)
1>
2> drop function myProc
3> drop table employee
4> GO
1>