diff --git a/html/inc/util_ops.inc b/html/inc/util_ops.inc
index 467e82851c..8810fe62c4 100644
--- a/html/inc/util_ops.inc
+++ b/html/inc/util_ops.inc
@@ -355,5 +355,35 @@ if (!isset($skip_auth_ops) && array_key_exists("SERVER_PORT", $_SERVER)) {
     auth_ops();
 }
 
+// TODO: use DB interface layer
+//
+function cancel_wus_where($clause) {
+    $q1 = "CREATE TEMPORARY TABLE tmp SELECT id FROM workunit WHERE $clause;";
+    $q2 = "UPDATE result SET server_state=5, outcome=5 WHERE server_state=2 AND workunitid in (SELECT id FROM tmp);";
+    $q3 = "UPDATE workunit SET error_mask=error_mask|16 WHERE id in (SELECT id FROM tmp);";
+    $q4 = "UPDATE workunit SET transition_time=0 WHERE id in (SELECT id FROM tmp);";
+    $q5 = "DROP TABLE tmp;";
+
+    if (!mysql_query($q1)) {
+        echo "MySQL command '$q1' failed:<br/>unable to create temporary WU id table.<br>\n";
+        return 1;
+    } else if (!mysql_query($q2)) {
+        echo "MySQL command '$q2' failed:<br/>unable to cancel unsent results.<br>\n";
+        mysql_query($q5);
+        return 2;
+    } else if (!mysql_query($q3)) {
+      echo "MySQL command '$q3' failed:<br/>unable to cancel workunits.<br>\n";
+        mysql_query($q5);
+        return 3;
+    } else if (!mysql_query($q4)) {
+        echo "MySQL command '$q4' failed:<br/>unable to trigger transitioner.<br>\n";
+        mysql_query($q5);
+        return 4;
+    } 
+    mysql_query($q5);
+    echo "Successfully canceled WUs WHERE '$clause'<br>\n";
+    return 0;
+}
+
 $cvs_version_tracker[]="\$Id$";  //Generated automatically - do not edit
 ?>
diff --git a/html/ops/cancel_workunits.php b/html/ops/cancel_workunits.php
new file mode 100644
index 0000000000..57a4ac33d1
--- /dev/null
+++ b/html/ops/cancel_workunits.php
@@ -0,0 +1,158 @@
+<?php
+// This file is part of BOINC.
+// http://boinc.berkeley.edu
+// Copyright (C) 2015 University of California
+//
+// BOINC is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License
+// as published by the Free Software Foundation,
+// either version 3 of the License, or (at your option) any later version.
+//
+// BOINC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
+
+// web interface for canceling WUs according to a SQL where clause
+
+// TODO: use get_int() etc.
+
+require_once("../inc/util_ops.inc");
+
+admin_page_head("Cancel Jobs");
+
+$limit = 100;
+if (array_key_exists('limit',$_REQUEST)) {
+    $nlimit=$_REQUEST['limit'];
+    if ($nlimit != 0) {
+        $limit = $nlimit;
+    }
+}
+
+$clause = "";
+
+if (array_key_exists('minid',$_REQUEST) && $_REQUEST['minid'] != "" &&
+    array_key_exists('maxid',$_REQUEST) && $_REQUEST['maxid'] != "")
+    $clause = "id >=" . $_REQUEST['minid'] . " AND id <=" . $_REQUEST['maxid'];
+else if (array_key_exists('list',$_REQUEST) && $_REQUEST['list'] != "")
+    $clause = "id IN (" . $_REQUEST['list'] . ")";
+else if (array_key_exists('uclause',$_REQUEST) && $_REQUEST['uclause'] != "")
+    $clause = urldecode($_REQUEST['uclause']);
+else if (array_key_exists('clause',$_REQUEST) && $_REQUEST['clause'] != "")
+    // the following line is BS, but apparently I can't find another way to pass a
+    // double quote (") to the query
+    $clause = str_replace('\"', '"', $_REQUEST['clause']);
+
+if ($clause == "") {
+
+    // copied from old cancel_wu_form.php
+    echo "<p>
+    This form may be used to cancel unnecessary or unwanted jobs.
+    We recommend that you stop the project before doing this.
+    Note that the jobs and their corresponding
+    results (if any) are NOT removed from the database.
+    Instead, they are marked as 'no longer needed'.
+    In most cases you should probably only remove jobs whose results
+    are all unsent,
+    since otherwise a user will not get credit
+    for a result that they might return.
+    </p>
+    <p>
+    Please specify jobs by ID range, ID list or clause to be used in a
+    'SELECT FROM workunit WHERE' query.
+    </p>
+    <p>
+    You will be given a list of jobs matching your specification
+    for confirmation before these are actually canceled.
+    </p>
+";
+
+    $page = $_SERVER["REQUEST_URI"];
+    echo "<form action=\"$page\" method=\"get\" enctype=\"application/x-www-form-urlencoded\">\n";
+    echo "<ul><li>\n";
+    echo ' Range: ID of first WU to cancel ';
+    echo '<input name="minid" type="text" size="10" maxlength="15">';
+    echo ' ID of last WU to cancel ';
+    echo '<input name="maxid" type="text" size="10" maxlength="15">';
+    echo "</li><li>\n";
+    echo ' Comma-separated list of IDs ';
+    echo '<input name="list" type="text" size="100" maxlength="200">';
+    echo "</li><li>\n";
+    echo ' WHERE clause (w/o "WHERE") ';
+    echo '<input name="clause" type="text" size="100" maxlength="200">';
+    echo "</li></ul>\n";
+    echo "<p>\n";
+    echo ' Limit ';
+    echo "<input name=\"limit\" type=\"text\" size=\"3\" maxlength=\"3\" value=\"$limit\">";
+    echo "</p>\n";
+    echo "<p>\n";
+    echo '<input type="submit" value="Cancel jobs">';
+    echo "</p>\n";
+
+} else { // if ($clause)
+
+    db_init(true); // try to get list of WUs from replica
+
+    $query = "SELECT id, name FROM workunit WHERE canonical_resultid = 0 AND error_mask = 0 AND $clause;";
+    $dbresult = mysql_query($query);
+
+    if (!$dbresult) {
+        echo "Error in query '$query'<br>\n";
+    } else {
+
+        echo "<form action=\"cancel_workunits_action.php\" method=\"post\">\n";
+        echo "<input type=\"hidden\" name=\"back\" value=\"cancelwus\"/>";
+
+        echo "<br><table border=\"1\">\n";
+        echo "<tr><th>WU ID</th><th>WU name</th></tr>\n";
+
+        $rescount = 0;
+        while ($res = mysql_fetch_object($dbresult)) {
+            if ($rescount < $limit) {
+                $id = $res->id;
+                echo "<tr>\n";
+
+                echo "<td align=\"left\" valign=\"top\">";
+                echo "<input type=\"checkbox\" name=\"WU[]\" value=\"$id\" checked>\n";
+                echo "<a href=db_action.php?table=workunit&detail=high&id=";
+                echo $id;
+                echo ">";
+                echo $id;
+                echo "</a>";
+                echo "</td>\n";
+
+                echo "<td align=\"left\" valign=\"top\">";
+                echo $res->name;
+                echo "</td>\n";
+
+                echo "</tr>\n";
+            }
+            $rescount++;
+        } // while (mysql_fetch_object())
+
+        mysql_free_result($dbresult);
+
+        echo "</table>\n<p>";
+        echo $rescount;
+        echo " WUs match the query ($query)\n</p>";
+
+        echo "<p>";
+        echo "<input type=\"hidden\" name=\"cancel\" value=\"1\"/>";
+        echo "<input type=\"hidden\" name=\"limit\" value=\"$limit\"/>";
+        $eclause = urlencode($clause);
+        echo "<input type=\"hidden\" name=\"clause\" value=\"$eclause\"/>";
+        echo "<input type=\"submit\" value=\"Cancel checked WUs\">";
+        echo "</p>\n";
+        echo "</form>\n";
+
+    } // if (!$dbresult)
+
+} // if ($clause)
+
+admin_page_tail();
+
+$cvs_version_tracker[]="\$Id$";  //Generated automatically - do not edit
+?>
diff --git a/html/ops/cancel_workunits_action.php b/html/ops/cancel_workunits_action.php
new file mode 100644
index 0000000000..020c188d82
--- /dev/null
+++ b/html/ops/cancel_workunits_action.php
@@ -0,0 +1,68 @@
+<?php
+// This file is part of BOINC.
+// http://boinc.berkeley.edu
+// Copyright (C) 2015 University of California
+//
+// BOINC is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License
+// as published by the Free Software Foundation,
+// either version 3 of the License, or (at your option) any later version.
+//
+// BOINC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
+
+require_once("../inc/util_ops.inc");
+
+admin_page_head("Cancel Workunits");
+
+// check for WUs to cancel
+$WUs="";
+if (array_key_exists('cancel',$_REQUEST) && ($_REQUEST['cancel'] == 1)) {
+    if (is_array($_REQUEST['WU'])) {
+        foreach ($_REQUEST['WU'] as $key => $value) {
+            if($WUs != "")
+                $WUs = $WUs . ",";
+            $WUs = $WUs . $value;
+        }
+    }
+}
+
+// cancel WUs (if not in rops)
+if($WUs != "") {
+    echo "<!--- WUs to cancel: $WUs --->\n";
+    if (!in_rops()) {
+        db_init();
+        cancel_wus_where("id IN (" . $WUs . ")");
+    }
+}
+
+if (array_key_exists('back',$_REQUEST)) {
+    if ($_REQUEST['back'] == "errorwus") {
+        echo "<p><a href=\"errorwus.php\">Return to All-error Workunits page</a></p>";
+    } else if ($_REQUEST['back'] == "cancelwus") {
+        if (array_key_exists('clause',$_REQUEST)) {
+            $limit = 20;
+            if (array_key_exists('limit',$_REQUEST))
+                $limit=$_REQUEST['limit'];
+            $clause=urlencode($_REQUEST['clause']);
+            echo "<p><a href=\"cancel_workunits.php?limit=$limit&uclause=$clause\">";
+            echo "Cancel next (max $limit) Workunits</a></p>";
+        }
+        echo "<p><a href=\"cancel_workunits.php\">Return to Cancel Workunits page</a></p>";
+    }
+}
+
+echo "<p>";
+echo "Page last updated ";
+echo time_str(time());
+echo "</p>\n";
+
+admin_page_tail();
+
+$cvs_version_tracker[]="\$Id$";  //Generated automatically - do not edit
+?>
diff --git a/html/ops/index.php b/html/ops/index.php
index d813027b58..aa9c6e0dec 100644
--- a/html/ops/index.php
+++ b/html/ops/index.php
@@ -108,7 +108,8 @@ echo "
         <li><a href=\"manage_app_versions.php\">Manage application versions</a></li>
         <li> Manage jobs
         <ul>
-            <li><a href=\"cancel_wu_form.php\">Cancel jobs</a>
+            <li><a href=\"cancel_wu_form.php\">Cancel jobs by ID</a>
+            <li><a href=\"cancel_workunits.php\">Cancel jobs by SQL clause</a>
             <li><a href=transition_all.php>Transition jobs</a>
               <p class=\"text-muted\">(this can 'unstick' old jobs)</p>
             <li><a href=\"revalidate.php\">Re-validate jobs</a>