Show duplicate records

Question

I have this request

SELECT id, timeOrdered, order_desc, firstname, lastname FROM `db`.`myTable` WHERE `myTable`.`customer_number` IN (100, 101, 102, 103, 104, 105) 

I am trying to find duplicate entries. If timeOrdered, order_desc, firstname, lastname match, then its cheating.

What will be the request for this Thanks

Answer 1

To find out what duplicates mean:

  SELECT t.order_desc, t.firstname, t.lastname FROM db.mytable t WHERE t.customer_number IN (100, 101, 102, 103, 104, 105) GROUP BY t.order_desc, t.firstname, t.lastname, t.timeordered HAVING COUNT(*) > 1 

To view the entire record associated with these duplicates:

 SELECT x.* FROM db.mytable x WHERE EXISTS(SELECT NULL FROM db.mytable t WHERE t.customer_number IN (100, 101, 102, 103, 104, 105) AND t.order_desc = x.order_desc AND t.firstname = x.firstname AND t.lastname = x.lastname AND t.timeordered = x.timeordered GROUP BY t.order_desc, t.firstname, t.lastname, t.timeordered HAVING COUNT(*) > 1) WHERE x.customer_number IN (100, 101, 102, 103, 104, 105) 

Answer 2

 SELECT DISTINCT t1.id FROM mytable t1 INNER JOIN mytable t2 ON t1.timeordered = t2.timeordered AND t1.order_desc = t2.order_desc AND t1.firstname = t2.firstname AND t1.lastname = t2.lastname AND t1.id <> t2.id