title: when using "SELECT varname = something + something etc. I cannot then do "WHERE varname = ..."
body: <p>I have:</p>
  <pre><code> SELECT KEYWORDS = CAST(USRN AS VARCHAR(15)) + ' ' + 
   RTRIM(SD) + ' ' + RTRIM(NL.LOCALITY_NAME) + ' ' + 
   RTRIM(NT.TOWN_NAME) + ' ' + RTRIM(NA.AUTHORITY_NAME)
  </code></pre>
  <p>That gives me what looks like a column, but is not:</p>
  <p><a href="https://i.stack.imgur.com/H5COE.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/H5COE.png" alt="enter image description here" /></a></p>
  <p>I want to have it so my code only selects the rows from KEYWORDS that match whatever the user is typing. Normally, if KEYWORDS was a column, I would write:</p>
  <pre><code>SELECT .... WHERE KEYWORDS = '%whateverTheUserIsTyping%'
  </code></pre>
  <p>but I cannot because keywords is not a real column and it is telling me that it does not exist.</p>
  <p>How do I get around this? thanks</p>