SELECT DISTINCT with LEFT JOIN, ORDERed BY in t-SQL

Question

I have the following table in SQL Server 2008:

CREATE TABLE tbl (ID INT, dtIn DATETIME2, dtOut DATETIME2, Type INT)

INSERT tbl VALUES
(1, \'05:00\', \'6:00\', 1         


        

Answer 1

You must include the column tbl.dtOut in your select list so it knows what to order on.

SELECT DISTINCT tbl.id, tbl.dtOut FROM tbl   
  LEFT JOIN tbl AS t1
  ON tbl.type = t1.type AND
     tbl.dtIn = t1.dtIn
  ORDER BY tbl.dtOut ASC