For this there are few tricks or the functionalities given by SQL.
1) Using a OUTPUT
variable inside the dynamic query that sends the result of the dynamic query
2) Executing the query with sp_executesql
3) Use of nVarchar type for cerating the dynamic queryThe simple code goes as :
DECLARE @ValOut bigint
N'SELECT TOP 1 @outPutValue = memberid FROM as_tblmembers order by 1 desc'
,N'@outPutValue bigint OUTPUT'