SQL Server determines whether duplicate values

A string of "1;2;1;1;1".
Excuse me:
How to implement the following features in SQL Server:
1. Determine if there are duplicate numbers in the string
If there are duplicate numbers, an error message is returned
If there are no duplicate numbers, the return is correct.


Idea: Splitting a string, depositing a substring into a temporary table, and grouping judgment on a temporary table

Create function repeatstring (@input varchar (8000), @separator varchar) returns  INTAS begin        Declare @temp Table (part varchar)  declare @i int, @result int set @input =rtrim (LTrim (@input))     set @i=charindex (@ Separator, @input) while     @i>=1     begin         Inserts @temp values (left (@input, @i-1))         set @input =substring (@input, @i+1,len (@input) [email protected])         Set @i=charindex (@separator, @input)     end     if exists (select Part,count (*) from @temp GROUP by part has count (*) >1)   Set @result = 1--there   is duplicate else    set @result = 0--There is no duplicate   return   @resultendgo

--Test

Select  dbo. Repeatstring (' 1,1,2,3,1 ', ', ')  --1select  dbo. Repeatstring (' 1,2,3,4,5 ', ', ')  --0

SQL Server determines whether duplicate values