sqlserver取字符串拼音首字母

sqlserver 使用函数获取一个字符串的拼音首字母

create function dbo.fn_getpinyin
(
    @str nvarchar(max)
)
returns nvarchar(max)
as
begin
    declare @word nchar(1),@py nvarchar(max)

    set @py=''

    while len(@str)>0
    begin
        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)

        set @str=right(@str,len(@str)-1)
    end

    return @py
end