SQL SERVER get the data with the smallest difference

       Share a little trick to get the data with the smallest difference with yourself. The test data is as follows:

--Test Data
if not object_id(N'Tempdb..#T1') is null
	drop table #T1
Go
Create table #T1([code] int,[value] int)
Insert #T1
select 1,10 union all
select 2,50 union all
select 3,100
GO
if not object_id(N'Tempdb..#T2') is null
	drop table #T2
Go
Create table #T2([code] int,[value] int)
Insert #T2
select 1,15 union all
select 2,35 union all
select 3,45
Go
-- end of test data

       Use the ABS function to achieve:

SELECT *,
       (
           SELECT TOP 1 [value] FROM #T2 ORDER BY ABS(#T1.value - #T2.value)
       )
FROM #T1;

       The result is as follows: