title: SQL COLUMN Update
body: <pre><code>Select * from a 
  inner join b 
  on a.1=b.2
  
  update table a 
  set a.2=b.3 
  from a 
  inner join b 
  on a.1=b.2
  </code></pre>
  
  <p>I am trying to update a column in a table in SQL.</p>
  
  <p>Initially I am selecting the data from the column using a join which rows needs to be updated (count would be 40000). Then I run the update statement to update the column with new values (updated count 2000). The count from join is always more than the update count.</p>
  
  <p>When i go back and perform the join I get count as zero.</p>
  
  <p>I couldn't understand why I am getting the difference. Can anyone please assist?</p>
  
  <p>Thanks</p>