title: Joining 3 tables pgsql
body: <p>I have 3 tables as shown below</p>
  
  <pre><code>table 1
  ________________________________________________
  id | effective_date     | table_3_id | acc_name |
  ___|____________________|____________|__________|
  112|2012-02-01 12:00:00 |     23     | Over Pay |
  ___|____________________|____________|__________|
  
  table 2
  __________________________________
  id    | table_1_id     | amount  |
  ______|________________|_________|
   1    |    112         |  400.00 |
  ______|________________|_________|
  
  table 3
  ________________________________________
  id  | emp_num  | first_name  | last_name|
  ____|__________|_____________|__________|
   23 |   100004 |   John      |    Doe   |  
  ____|__________|_____________|__________|
  </code></pre>
  
  <p>I have a start date and an end date and also a predefined value for acc_name. What I want to do is, to retrieve the emp_num, first_name, last_name and amount from relevant tables that have a effective_date that falls between start date and end date and also the acc_name should be the predefined value.</p>
  
  <p>For above tables if my start date = 2012-01-30 12:00:00 , end date = 2012-03-01 12:00:00 and acc_name = Over Pay; then below values should be returned.</p>
  
  <pre><code>emp_num = 100004  
  first_name = John  
  last_name = Doe  
  amount = 400.00
  </code></pre>
  
  <p>How can I do this? I am not sure whether joining all 3 the tables is the best approach here. Can anyone help?  </p>