2 inner joins sql how does that work code example

Example: two inner joins

SELECT 
  c.*, i.*, a.* 
FROM 
  invoices i 
INNER JOIN 
  client c 
ON 
  i.clientid = c.clientid 
INNER JOIN 
  address a 
ON 
  a.clientid = c.clientid 
WHERE 
  i.id = 21