title: select specific rows in SAS
body: <p>I have following data with multiple recording from single patient.</p>
  
  <pre><code>ID                       date           day     result
  BELF000000084785    20111110    1   164
  BELF000000084785    20111202    2   172
  BELF000016833470    20070122    2   226
  BELF000016833470    20070522    3   398
  BELF000016959442    20080429    1   242
  BELF000016959442    20080820    1   126
  BELF000016959442    20090225    2   302
  BELF000016959442    20090424    2   320
  BELF000017061714    20080626    1   152
  BELF000017801424    20110803    1   298
  BELF000017801424    20110913    2   252
  BELF000017801424    20111022    3   234
  BELF000024405407    20080218    1   232
  BELF000024405407    20080318    2   190
  BELF000024405410    20070122    3   380
  BELF000024405410    20070218    1   506
  BELF000024405410    20070320    2   480
  BELF000024405410    20070626    3   346
  BELF000024408114    20070423    1   296
  BELF000024408114    20070711    3   294
  </code></pre>
  
  <p>I want to extract the patients with records in  day 1 ; if day 1 and day 2 both available and day1 day2 and day3 all available. and through away other. any sas help.</p>