A SQL query to find duplicates in a table.

• Use the GROUP BY clause to group the records by the columns that may have duplicates.

• Use the HAVING clause to filter the groups that have more than one record...read more

Select distinct column name from table name;

Select ename, count(*) from emp group by ename having count(*) >1;

Select primary_key, count(*) from table group by primary_key having count(*)>1