title: Error Code: 1054 Unknown column 'tzHour' in 'where clause'
body: <p>trying to get the following to work, trying to make adjustment for timezone. If I comment out the line AND plan.resetHour=tzHour it shows the column tzHour correctly but can't seem to use the value in the where clause.</p>
  
  <pre><code>SELECT
       `issuer`.`tz`
      ,`account`.`id`
      , `plan`.`endDate`
      , `plan`.`resetDay`
      , `plan`.`resetHour`
      , `plan`.`type`
      , HOUR(NOW())
      ,   CASE issuer.`tz`
          WHEN 'US/Eastern' THEN HOUR(NOW())+1
          WHEN 'US/Central' THEN HOUR(NOW())
          ELSE HOUR(NOW())
      END AS tzHour
  
  FROM
      `dvh`.`account`
      INNER JOIN `dvh`.`plan` 
          ON (`account`.`plan` = `plan`.`id`)
      INNER JOIN `dvh`.`issuer` 
          ON (`plan`.`issuer` = `issuer`.`id`)        
  WHERE plan.type='UNIT' 
  AND plan.startDate &lt; NOW() 
  AND plan.endDate &gt;NOW() 
  AND plan.resetDay=DAYOFWEEK(NOW())
  AND plan.resetHour=tzHour
  AND account.`active`=1;
  </code></pre>