明牌出現頻率機

題目:將某段期間開出的號碼由最舊到最新的排列為原始資料
希望可以秀出開獎號碼由最近出現的排到更早出現的順序




declare @length int = (select LEN('277854130636666023097111131915'))
--計算近期開獎號碼字串長度
declare @i int = @length
declare @result varchar(10)
declare @char varchar(1)
--set @char = substring('277854130636666023097111131915',30,1)
--print @char
--select @result
while @i>0
begin
set @char = substring('277854130636666023097111131915',@i,1)
--print @char
if ((select charIndex(@char, @result)) is null )
begin
set @result = @char
--print @char
end
if ((select charIndex(@char, @result)) = 0 )
begin
set @result = @result+@char
--print @char
end
--print substring('277854130636666023097111131915',@i,1)
set @i = @i - 1
end
print @result