sql 随笔 2015-07-02

sql 自定义函数

 --检查函数是否存在
 if exists (select * from dbo.sysobjects where id = object_id(N'dbo.pTitleCase') and xtype in (N'FN', N'IF', N'TF'))
  drop function dbo.pTitleCase  ;
 go
 
--创建函数
create function dbo.pTitleCase(@strIn nvarchar(Max))
	returns nvarchar(Max)
as
	begin;
		declare
		@strOut nvarchar(max),
		@currentPostion int,
		@nextSpace int,
		@currentWord nvarchar(max),
		@strLen int,
		@lastWord bit;
 
	set @nextSpace = 1;
	set @currentPostion =1;
	set @strOut ='';
	set @strLen=Len(@strIn);
	set @lastWord=0;
 
	while @lastWord=0
		begin;
			set @nextSpace=CharIndex( ' ',@strIn,@currentPostion+1)
			if @nextSpace=0 --no more spaces found
				begin;
					set @nextSpace=@strLen;
					set @lastWord=1;
				end;
 
			set @currentWord = Upper(substring(@strIn,@currentPostion,1));
			set @currentWord = @currentWord + lower(substring(@strin,@currentPostion+1,@nextSpace-@currentPostion));
			set @strOut=@strOut+@currentWord;
			set @currentPostion=@nextSpace+1;
		end;
	return @strOut;
end;
go	
 
--执行函数
SELECT [Demo].[dbo].[pTitleCase] ( 'one TWO tHrEe')
go