Sort 26 letters, Chinese characters, and first letter

Alter function f_getpy (@ STR nvarchar (4000 ))
Returns nvarchar (4000)
As
Begin
Declare @ strlen int, @ Re nvarchar (4000)
Declare @ t table (CHR nchar (1) Collate chinese_prc_ci_as, letter nchar (1 ))
Insert into @ T (CHR, letter)
Select 'ay', 'A' Union all select '8', 'B' Union all
Select 'accept', 'C' Union all select 'accept', 'D' Union all
Select 'hangzhou', 'E' Union all select 'hangzhou', 'F' Union all
Select 'hangzhou', 'G' Union all select 'haid', 'H' Union all
Select ', 'J' Union all select 'hour', 'K' Union all
Select 'hangzhou', 'L' Union all select 'hangzhou', 'M' Union all
Select 'hour', 'n' Union all select 'ou', 'O' Union all
Select 'hangzhou', 'P' Union all select '7', 'q' Union all
Select 'hour', 'R' Union all select 'hour', 's' Union all
Select 'others', 't'union all select 'hour', 'w' Union all
Select 'Xi ', 'x' Union all select 'ya', 'y' Union all
Select 'running', 'Z'
Select @ strlen = Len (@ Str), @ Re =''
While @ strlen> 0
Begin
Select top 1 @ Re = letter + @ Re, @ strlen = @ strlen-1
From @ t a where CHR <= substring (@ STR, @ strlen, 1)
Order by CHR DESC
If @ rowcount = 0
Select @ Re = substring (@ STR, @ strlen, 1) + @ Re, @ strlen = @ strlen-1
End
Return (@ Re)
End
Go
Create proc pr_getpy
@ Firstword nchar (1)
As
Select * From aspnet_users where @ firstword = substring (DBO. f_getpy (username), 1, 1)
Go
Exec pr_getpy @ firstword = 'Z'
Write it down first.