If a column has expression as value, the column does not exist in where clause.
Example:
Table news has a expression column sent. Filter creates the following query:
SELECT news.id,
news.title,
news.sent_on,
(CASE WHEN news.sent_on IS NOT NULL THEN 1 ELSE 0 END) AS sent,
FROM news
WHERE news.sent = 1 // column sent does not exist here
ORDER BY news.sent_on DESC;
Additional:
Have a look at this Stack Overflow example