diff --git a/backend.php b/backend.php
index 41b2c29db..3975cd3b7 100644
--- a/backend.php
+++ b/backend.php
@@ -1125,7 +1125,9 @@
 		print "<p><table width=\"100%\" class=\"prefLabelList\" id=\"prefLabelList\">";
 
 		print "<tr class=\"title\">
-					<td width=\"5%\">Select</td><td width=\"40%\">SQL expression</td>
+					<td width=\"5%\">Select</td><td width=\"40%\">SQL expression
+					<a class=\"helpLink\" href=\"javascript:popupHelp(1)\">(?)</a>
+					</td>
 					<td width=\"40%\">Caption</td></tr>";
 		
 		$lnum = 0;
@@ -1220,5 +1222,57 @@
 		print "</div>";
 	}
 
+	if ($op == "help") {
+		print "<html><head>
+			<title>Tiny Tiny RSS : Help</title>
+			<link rel=\"stylesheet\" href=\"tt-rss.css\" type=\"text/css\">
+			<script type=\"text/javascript\" src=\"functions.js\"></script>
+			<script type=\"text/javascript\" src=\"feedlist.js\"></script>
+			<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">
+			</head><body>";
+
+		$tid = sprintf("%d", $_GET["tid"]);
+
+		/* FIXME this badly needs real implementation */
+
+		print "<div class='helpResponse'>";
+
+		?>
+
+		<h1>Help for SQL expressions</h1>
+
+		<h2>Description</h2>
+
+		<p>The &laquo;SQL expression&raquo; is added to WHERE clause of
+			view feed query. You can match on most fields of ttrss_entries table
+			and even use subselect to query additional information. This 
+			functionality is considered to be advanced and requires basic
+			understanding of SQL.</p>
+			
+		<h2>Examples</h2>
+
+		<pre>unread = true</pre>
+
+		Matches all unread articles
+
+		<pre>title like '%Linux%'</pre>
+
+		Matches all articles which mention Linux in the title. You get the idea.
+
+		<p>See the database schema included in the distribution package for gruesome
+		details.</p>
+
+		<?
+
+		print "<div align='center'>
+			<a class=\"helpLink\"
+			href=\"javascript:window.close()\">(Close this window)</a></div>";
+
+		print "</div>";
+
+		print "</body></html>";
+
+	}
+
 	db_close($link);
 ?>
diff --git a/functions.js b/functions.js
index 323d7d8af..5bf5e6973 100644
--- a/functions.js
+++ b/functions.js
@@ -356,3 +356,9 @@ function update_label_counters(feed) {
 		xmlhttp_rpc.send(null);
 	}
 }
+
+function popupHelp(tid) {
+	var w = window.open("backend.php?op=help&tid=" + tid,
+		"Popup Help", 
+		"menubar=no,location=no,resizable=yes,scrollbars=yes,status=no");
+}
diff --git a/tt-rss.css b/tt-rss.css
index 2a9af4ae6..5c81a3154 100644
--- a/tt-rss.css
+++ b/tt-rss.css
@@ -352,3 +352,38 @@ table.prefFeedList tr.title td, table.prefFilterList tr.title td,
 	border-style : solid;
 }
 
+a.helpLink {
+	color : #808080;
+}
+
+a.helpLink:hover {
+	color : #5050aa;
+}
+
+div.helpResponse {
+	margin : 10px;
+	background-image : url("images/vgrad_light_rev2.png");
+	background-position : top left;
+	background-repeat : repeat-x;
+	padding : 10px 20px 10px 20px;
+	border : 1px solid #f0f0f0;
+}
+
+div.helpResponse h1 {
+	border-width : 0px 0px 1px 0px;
+	border-style : solid;
+	border-color : #c0c0c0;
+	font-size : 16pt;
+}
+
+div.helpResponse h2 {
+	border-width : 0px 0px 0px 0px;
+	font-size : 12pt;
+
+}
+
+pre {
+	border : 1px solid #c0c0c0;
+	padding : 5px;
+	background : #f0f0f0;
+}
diff --git a/tt-rss_compact.css b/tt-rss_compact.css
index 7f49402de..cef4e47dc 100644
--- a/tt-rss_compact.css
+++ b/tt-rss_compact.css
@@ -379,3 +379,38 @@ table.prefFeedList tr.title td, table.prefFilterList tr.title td,
 	font-size:9pt;
 }
 
+a.helpLink {
+	color : #808080;
+}
+
+a.helpLink:hover {
+	color : #5050aa;
+}
+
+div.helpResponse {
+	margin : 10px;
+	background-image : url("images/vgrad_light_rev2.png");
+	background-position : top left;
+	background-repeat : repeat-x;
+	padding : 10px 20px 10px 20px;
+	border : 1px solid #f0f0f0;
+}
+
+div.helpResponse h1 {
+	border-width : 0px 0px 1px 0px;
+	border-style : solid;
+	border-color : #c0c0c0;
+	font-size : 16pt;
+}
+
+div.helpResponse h2 {
+	border-width : 0px 0px 0px 0px;
+	font-size : 12pt;
+
+}
+
+pre {
+	border : 1px solid #c0c0c0;
+	padding : 5px;
+	background : #f0f0f0;
+}
