實現方法：

--函數

Create function [dbo].[fn_GetPy](@str nvarchar(4000)) 

returns nvarchar(4000) 
--用於加密
--WITH ENCRYPTION 
as 
begin 
declare @intLen int 
declare @strRet nvarchar(4000) 
declare @temp nvarchar(100) 
set @intLen = len(@str) 
set @strRet = ‘‘ 
while @intLen > 0 
begin 
set @temp = ‘‘ 
select @temp
 
 = case 
when substring(@str,@intLen,1) >= ‘帀‘ then ‘Z‘ 
when substring(@str,@intLen,1) >= ‘丫‘ then ‘Y‘ 
when substring(@str,@intLen,1) >= ‘夕‘ then ‘X‘ 
when substring(@str,@intLen,1) >= ‘屲‘ then ‘W‘ 
when substring(@str,@intLen,1) >= ‘他‘ then ‘T‘ 
when substring(@str,@intLen,1) >=
 
 ‘仨‘ then ‘S‘ 
when substring(@str,@intLen,1) >= ‘呥‘ then ‘R‘ 
when substring(@str,@intLen,1) >= ‘七‘ then ‘Q‘ 
when substring(@str,@intLen,1) >= ‘妑‘ then ‘P‘ 
when substring(@str,@intLen,1) >= ‘噢‘ then ‘O‘ 
when substring(@str,@intLen,1) >= ‘拏‘ then ‘N‘ 
when substring(@str,@intLen,1) >=
 
 ‘嘸‘ then ‘M‘ 
when substring(@str,@intLen,1) >= ‘垃‘ then ‘L‘ 
when substring(@str,@intLen,1) >= ‘哢‘ then ‘K‘ 
when substring(@str,@intLen,1) >= ‘丌‘ then ‘J‘ 
when substring(@str,@intLen,1) >= ‘鉿‘ then ‘H‘ 
when substring(@str,@intLen,1) >= ‘旮‘ then ‘G‘ 
when substring(@str,@intLen,1) >= ‘發‘ then ‘F‘ 
when substring(@str,@intLen,1) >= ‘妸‘ then ‘E‘ 
when substring(@str,@intLen,1) >= ‘咑‘ then ‘D‘ 
when substring(@str,@intLen,1) >= ‘嚓‘ then ‘C‘ 
when substring(@str,@intLen,1) >= ‘八‘ then ‘B‘ 
when substring(@str,@intLen,1) >= ‘吖‘ then ‘A‘ 
else rtrim(ltrim(substring(@str,@intLen,1))) 
end 
--對於漢字特殊字符，不生成拼音碼 
if (ascii(@temp)>127) set @temp = ‘‘ 
--對於英文中小括號，不生成拼音碼 
if @temp = ‘(‘ or @temp = ‘)‘ set @temp = ‘‘ 
select @strRet = @temp + @strRet 
set @intLen = @intLen - 1 
end 
return lower(@strRet) 
end

--執行語句

declare @id int; 
declare @UserName varchar(100); 
declare @cursor cursor;--遊標
set @cursor=cursor for 
select id,UserName from T_user;    
open @cursor
fetch next from @cursor into @id,@UserName;
while @@FETCH_STATUS=0
begin
begin
update T_user set UserName=(SELECT [dbo].[fn_GetPy](@UserName)) where id=@id
end
fetch next from @cursor into @id,@UserName;
end
close @cursor
deallocate @cursor

原文地址：https://www.cnblogs.com/gqrbkw/p/4724533.html

SQL將用戶表中已存在的數據所有姓名（漢字）轉換為拼音首字母