Select where count of one field is greater than one

Question

I want to do something like this:

SELECT * 
  FROM db.table 
 WHERE COUNT(someField) > 1

How can I achieve this in MySql?

Answer 1

You can also do this with a self-join:

SELECT t1.* FROM db.table t1
JOIN db.table t2 ON t1.someField = t2.someField AND t1.pk != t2.pk