title: Select records where there are more than one value in one of the fields
body: <p>Could someone please help me with narrowing down my results? 
  Three tables facility, sample, location. With the code below, I get expected results but I would like to show only the records where the matrix code has more that one result (>1). In the example below, I would like to show only location code 0689. </p>
  
  <pre><code>SELECT DISTINCT f.facility_code, 
                  l.sys_loc_code, 
                  l.loc_type, 
                  s.matrix_code
  FROM dt_sample s join dt_location l on l.facility_id = s.facility_id AND l.sys_loc_code = s.sys_loc_code 
  JOIN dt_facility f on f.facility_id = l.facility_id
  WHERE l.loc_type ='TS'
  GROUP BY f.facility_code, l.sys_loc_code, l.loc_type, s.matrix_code
  HAVING COUNT(s.matrix_code)&gt;1
  ORDER BY f.facility_code, l.sys_loc_code, s.matrix_code
  
  facility_code   sys_loc_code    loc_type    matrix_code  
  DUR03           0687             TS         WATER        
  DUR03           0688             TS         WATER        
  DUR03           0689             TS         SEDIMENT     
  DUR03           0689             TS         SW           
  DUR03           0689             TS         WATER       
  </code></pre>
  
  <p>Thanks for your help.</p>