Duplicate Results In Sql Query Join. Dec 10 2013 0401 AM Samson sun - MFST LINK. SQL Join creates duplicates.
For our example my query looks like this. Try to run several times this query and youll see that results will vary from time to time. The end result is a massive table with mostly duplicates.
In our case we wanted to find duplicate birthdays.
Try to run several times this query and youll see that results will vary from time to time. WITH cte AS SELECT a b COUNT occurrences FROM t1 GROUP BY a b HAVING COUNT 1 SELECT t1id t1a t1b FROM t1 INNER JOIN cte ON ctea t1a AND cteb t1b ORDER BY t1a t1b. To return the entire row for each duplicate row you join the result of the above query with the t1 table using a common table expression CTE. In terms of the general approach for either scenario finding duplicates values in SQL comprises two key steps.