title: Unexpected Duplicate Results Returned from Statement - Unsure what is missing
body: <p>I have a query where I am investigating what wholesale price list (PRRF) was obtained and used to provide sales prices on orders and against this I want to see what the retail price is from the retail price list (PK01). I want to return the retail price list (PK01) only where it is like the wholesale price list (First letter of wholesale and retail price lists should be the same and can either start with M or S.</p>
  <p>what i was expecting to be returned for the example on order 1110003408 was this;</p>
  <pre><code>1001247 1110003408  SS21    USD S03 WHOLESALE   S04 RETAIL
  </code></pre>
  <p>what was returned for the example on order 1110003408 was this;</p>
  <pre><code>1001247 1110003408  SS21    USD S03 WHOLESALE   M04 RETAIL
  1001247 1110003408  SS21    USD S03 WHOLESALE   S04 RETAIL
  </code></pre>
  <p>This is my query;</p>
  <pre><code>select distinct
  t1.cuno as Customer,
  t1.orno as OrderNumber,
  t1.proj as Season,
  odhead.cucd as Currency,
  t1.prrf as WhslPriceList,
  t2.a030 as WhslPriceListName,
  t3.pk01 as RtlPriceList,
  t3.a030 as RtlPriceListName
  from odhead
  left join ooline t1 on t1.cono = odhead.cono
      and t1.cuno = odhead.cuno
      and t1.orno = odhead.orno
  left join cugex1 t2 on t2.cono = odhead.cono
      and t2.pk01 = t1.prrf
      and t2.pk02 = odhead.cucd
  left join cugex1 t3 on t3.cono = odhead.cono
      and t3.pk01 LIKE '[M,S]%'
      and t3.a130 = t1.proj
      and t3.pk02 = odhead.cucd 
      and t3.a030 &lt;&gt; 'WHOLESALE'
  where t1.orno = '1110003408'
  </code></pre>