Need extract following information

[orion_rus]

I have 2 tables:
Persons
id = personid
Contacts
id = contactid
personid -> Persons:personid

I need to extract information about persons who have exactly 2 contacts.
How it possible?
Thanks in advance

[coopster]

Use a GROUP BY clause with a HAVING clause:

SELECT 
 Persons.personid 
 FROM Persons 
 INNER JOIN Contacts ON Persons.personid = Contacts.personid 
 GROUP BY Persons.personid 
 HAVING COUNT(Contacts.personid) = 2 
;