SQL Server/T-SQL Tutorial/Procedure Function/Utility function
Содержание
Changing Character Values to Proper Case with user-defined functions
<source lang="sql">
3> 4> 5> CREATE TABLE employee( 6> id INTEGER NOT NULL PRIMARY KEY, 7> first_name VARCHAR(10), 8> last_name VARCHAR(10), 9> salary DECIMAL(10,2), 10> start_Date DATETIME, 11> region VARCHAR(10), 12> city VARCHAR(20), 13> managerid INTEGER 14> ); 15> 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> CREATE FUNCTION dbo.udf_ProperCase(@UnCased varchar(max)) 4> RETURNS varchar(max) 5> AS 6> BEGIN 7> SET @UnCased = LOWER(@UnCased) 8> DECLARE @C int 9> SET @C = ASCII("a") 10> WHILE @C <= ASCII("z") 11> BEGIN 12> SET @UnCased = REPLACE( @UnCased, " " + CHAR(@C), " " + CHAR(@C-32)) 13> SET @C = @C + 1 14> END 15> SET @UnCased = CHAR(ASCII(LEFT(@UnCased, 1))-32) + RIGHT(@UnCased,LEN(@UnCased)-1) 16> RETURN @UnCased 17> END 18> GO 1> 2> SELECT dbo.udf_ProperCase(first_name) 3> FROM employee 4> GO
Jason
Alison
James
Celia
Robert
Linda
David
James
Joan
(9 rows affected) 1> 2> drop function dbo.udf_ProperCase 3> GO 1> drop table employee; 2> GO 1> --Reference from: 2> --SQL Server 2005 T-SQL Recipes A Problem-Solution Approach 3></source>
Format a date
<source lang="sql">
3> CREATE FUNCTION MyDateFormat 4> (@indate datetime, 5> @Separator char(1)="-") 6> RETURNS nchar(20) 7> AS 8> BEGIN 9> RETURN 10> CONVERT(nvarchar(20), DATEPART(dd, @indate)) 11> + @Separator 12> + CONVERT(nvarchar(20), DATEPART(mm, @indate)) 13> + @Separator 14> + CONVERT(nvarchar(20), DATEPART(yy, @indate)) 15> END 16> GO 1> 2> SELECT dbo.MyDateFormat(GETDATE(), "*") 3> GO
17*8*2008 1> 2> 3> drop FUNCTION MyDateFormat; 4> GO</source>
if an int odd
<source lang="sql">
4> CREATE FUNCTION dbo.ufnIsOdd (@n int = 5) 5> RETURNS bit 6> AS 7> BEGIN 8> RETURN (@n % 2) 9> END 10> GO 1> 2> CREATE PROCEDURE usp_NumberIsOdd 3> @n int = 5 4> AS 5> SELECT @n "Number", @n % 2 "Is_odd = 1" 6> GO 1> 2> DECLARE @numb int 3> 4> SELECT @numb "Number", dbo.ufnIsOdd (@numb) "Is_odd = 1" 5> SELECT @numb "Number", dbo.ufnIsOdd (DEFAULT) "Is_odd = 1" 6> SET @numb = 6 7> SELECT @numb "Number", dbo.ufnIsOdd (@numb) "Is_odd = 1" 8> GO Number Is_odd = 1
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NULL NULL
(1 rows affected) Number Is_odd = 1
----------
NULL NULL
(1 rows affected) Number Is_odd = 1
----------
6 0
(1 rows affected) 1> 2> drop FUNCTION dbo.ufnIsOdd; 3> GO 1> 2> drop PROCEDURE usp_NumberIsOdd; 3> GO</source>
linear_max() Scalar Function
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6> CREATE FUNCTION dbo.linear_max 7> ( 8> @arg1 AS int, 9> @arg2 AS int 10> ) 11> RETURNS int 12> AS 13> BEGIN 14> RETURN CASE 15> WHEN @arg1 >= @arg2 THEN @arg1 16> WHEN @arg2 > @arg1 THEN @arg2 17> ELSE NULL 18> END 19> END 20> GO 1> 2> SELECT 3> dbo.linear_max(1, 2) 4> 5> drop function dbo.linear_max 6> GO
2
(1 rows affected) 1> 2></source>
Scalar Functions
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A scalar function accepts any number of parameters and returns one value. Input parameters are declared within parentheses followed by the return value declaration. All statements must be enclosed in a BEGIN. . . END block. 8> 9> CREATE FUNCTION fnGetAge (@BirthDate DateTime, @Today DateTime) 10> RETURNS Int 11> AS 12> BEGIN 13> RETURN DateDiff(day, @BirthDate, @Today) / 365.25 14> END 15> GO 1> 2> 3> drop function fnGetAge; 4> GO 1></source>
The linear_min Scalar Function
<source lang="sql">
4> CREATE FUNCTION dbo.linear_min( 5> @arg1 AS int, 6> @arg2 AS int 7> ) 8> RETURNS int 9> AS 10> BEGIN 11> RETURN CASE 12> WHEN @arg1 <= @arg2 THEN @arg1 13> WHEN @arg2 < @arg1 THEN @arg2 14> ELSE NULL 15> END 16> END 17> GO 1> GRANT EXECUTE ON dbo.linear_min TO public 2> GO 1> 2> drop function dbo.linear_min 3> GO</source>
