title: Can't get unique values joining two tables
body: <p>I have 2 tables that I need to join and select the unique rows from.  Here is a sample of my data: (there are more columns)</p>
  
  <pre><code>tbl1:
  MB# MBName  PCCNo_PRI   Primary_IP       PCCNo_SEC          Secondary_IP    ID
  100  name    0               10.1.9.10       30              10.1.9.10       1 
  103  name3   17              10.1.9.27       47              10.1.9.67       4
  403  name13  17              10.1.9.27       47              10.1.9.67       14
  </code></pre>
  
  <p>tbl2:</p>
  
  <pre><code>RTU PCC#_PRI    PCC#_SEC    STATION ADDRESS
  15  0           30          6
  52  12          42          1
  53* 17          47          1
  54  18          48          1
  63  9           39          2
  69* 17          47          2
  </code></pre>
  
  <p>I need to join the two tables and get the unique RTU(s) in tbl2 for a given MB# in tbl1.
  Query =</p>
  
  <pre><code>SELECT t1.MB#,t2.RTU,t2.[Device Manufacturer],t2.PCC#_PRI,t2.PCC#_SEC,t2.[STATION ADDRESS] 
  INTO C300_RTU_MASTERBLK_Map
  FROM mbm_PCDIMasterBlk_tbl as t1, dbo.WOA_PCC_Conn_tbl as t2
  WHERE t1.PCCNo_PRI = t2.PCC#_PRI
  </code></pre>
  
  <p>I am getting duplicate rows for tbl2 53 and 69 (* above).  53 ends up with 2 entries; one to 103 and one 403 (69 gets same).   How can I query this for unique RTU(s) to MB#?</p>