title: How in SQL do i get only the entries where the same value is in a single column for the whole table?
body: <p>So im stuck on trying to make an SQL that grabs every ROW who has the same value for a specific COLUMN.</p>
  
  <p>EXAMPLE:<br>
                                                                                             table: buyers           </p>
  
  <pre><code>aID | bID                        aID | bID
   1  |  3                          1  |  3 
   1  |  4                          1  |  2
   1  |  2                          2  |  2
   1  |  5                          1  |  4    this one also should return aID = 1
                                         since aID =1 is present for every different bID
  </code></pre>
  
  <p>I think I'm close with:</p>
  
  <pre><code>SELECT aID
    FROM buyers
   WHERE COUNT(bID) = (SELECT S1.aID
                         FROM buyers S1, 
                              buyers S2
                        WHERE S1.aID = S2.bID
                          AND S2.bID &lt;&gt; S1.bID)
  </code></pre>
  
  <p>it has to be in every row in a column or dont get it so if one <code>aID</code> was different then dont get it. an <code>aID</code> has to be matched to every <code>bID</code></p>