sql - Joining between several tables -

my question sql queries

using following tables:

1. consultant(id,name,skill)  2. customercompany(id,name address, phone, email, webaddr,market) 3. project(id,startdate,enddate,consultantid,customerid,days) 4. invoice(id,date,customer,amount,status)  

sql statement

find names of consultants worked customers in berlin , london

i think have join tables cant definite query, suggestions?

something like

select c.name consultant c --join on projects consultant worked on join project p on p.consultantid = c.consultantid --join on customer companies projects join customercompany cc on cc.id = p.customerid --addresses might have various formats, use operator cc.address '%london%' or cc.address '%berlin%' 

might trick.