Delete rows that match multiple columns of the same table

Question

Using SQL, I have 5 columns: ssn, lastname, firstname, RF and flag field . I need to go through this table and where 4 columns are equal to another row and the flag field value in this row is 2050, then delete this entry 2050.

Answer 1

delete from MyTable m where flag = 2050 and exists ( select 1 from MyTable where MyTable.ssn = m.ssn and MyTable.lastname=m.lastname and MyTable.firstname=m.firstname and MyTable.RF=m.RF and MyTable.flag <> 2050 ) 

Answer 2

 DELETE T1 FROM My_Table T1 INNER JOIN My_Table T2 ON T2.ssn = T1.ssn AND T2.last_name = T1.last_name AND T2.first_name = T1.first_name AND T2.RF_name = T1.RF_name AND T2.flag <> T1.flag WHERE T1.flag = 2050 

Answer 3

 delete from TableName as tn where tn.flag = 2050 and exists (select * from TableName as tn2 where tn.ssn = tn2.ssn and tn.lastname = tn2.lastname and tn.firstname = tn2.firstname and tn.rf = tn2.rf and tn2.flag <> 2050) 

Answer 4

 delete from Table1 where flag = 2050 and exists (select * from Table2 where ssn = Table1.ssn and lastname = Table1.lastname and firstname = Table1.firstname and rf = Table1.rf and flag <> 2050)