数据库按首字母查询方法

现在数据库中自定义函数：

create function fun_getFirstPY(@str nvarchar(4000))
returns nvarchar(4000)
as
begin
declare @word nchar(1),@PY nvarchar(4000)
set @PY=''
set @word=left(@str,1)
--如果非汉字字符，返回原字符
set @PY=@PY+(case when unicode(@word) between 19968 and 19968+20901
then (select top 1 PY from (
select 'A' as PY,N'驁' as word
union all select 'B',N'簿'
union all select 'C',N'錯'
union all select 'D',N'鵽'
union all select 'E',N'樲'
union all select 'F',N'鰒'
union all select 'G',N'腂'
union all select 'H',N'夻'
union all select 'J',N'攈'
union all select 'K',N'穒'
union all select 'L',N'鱳'
union all select 'M',N'旀'
union all select 'N',N'桛'
union all select 'O',N'漚'
union all select 'P',N'曝'
union all select 'Q',N'囕'
union all select 'R',N'鶸'
union all select 'S',N'蜶'
union all select 'T',N'籜'
union all select 'W',N'鶩'
union all select 'X',N'鑂'
union all select 'Y',N'韻'
union all select 'Z',N'咗'
) T
where word>=@word collate Chinese_PRC_CS_AS_KS_WS
order by PY ASC) else @word end)
return @PY
end

 

编程中代码：

select  xxxx  from xxxx   where dbo.fun_getFirstPY(categoryname)='W'