[firebird-support] How do find duplicates in a table?

['stwizard' stwiz...@att.net [firebird-support]]

Greetings All,

 

How do I form a SQL Select statement that will return which records in my 
PERSON table have duplicate SOC_SEC_NO.

 

In other words I need a list of persons where the social security number 
appears in the database more than once.  Some SOC_SEC_NO may be null which I do 
not care about.

 

PERSON:

PERSON_ID

SOC_SEC_NO

 

Any help appreciated,

Mike