SQL Lookup Duplicate rows

In a table, some fields are not primary keys and are not unique, but in the process of use, the field does not apply duplicates, and sometimes it repeats. So, to find the row for a repeating field, use the SQL statement:

--That is:--select * from table Where repeating field in (Select repeating field from table Group by repeating field having Count (*) >1)--to a specific example Select * from T_exte RM where Mainkeyindex in (select Mainkeyindex from T_exterm Group by Mainkeyindex have Count (*) >1)

SQL Lookup Duplicate rows