A common scenario when querying tables is the need
to find duplicate fields within the same table. To do this is simple; it
requires utilizing the GROUP BY clause and counting the number of recurrences.
For example, let’s take a employee table. Within the customers table, we want
to find all the records where the Employee Names are the same. We also want to
find which Employee Names are the same and count them.
Use below sql script
SELECT EmpName
,DuplicateCount = COUNT(1)
FROM [Emp]
GROUP BY EmpName
HAVING COUNT(1) > 1 -- more than one value
ORDER BY COUNT(1) DESC
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