Ето един вграден подход
Пример
Declare @List varchar(max)='212345, 312345, 145687, 658975, 256987, 365874, 568974, 124578, 125689'
Select A.AccountNumber
,A.EndDate
From Accounts A
Join (
Select RetSeq = Row_Number() over (Order By (Select null))
,RetVal = v.value('(./text())[1]', 'int')
From (values (convert(xml,'<x>' + replace(@List,',','</x><x>')+'</x>'))) x(n)
Cross Apply n.nodes('x') node(v)
) B on A.AccountNumber = B.RetVal
Order By B.RetSeq
RetSeq RetVal
1 212345
2 312345
3 145687
4 658975
5 256987
6 365874
7 568974
8 124578
9 125689