diff --git a/lib/models/BlubberThread.php b/lib/models/BlubberThread.php
index d0f2f89ecd7fd76b95e955b3f38e0b7e9b9dcb5b..f266223bdc3b1687c3984af7d875094ddf1df033 100644
--- a/lib/models/BlubberThread.php
+++ b/lib/models/BlubberThread.php
@@ -101,11 +101,11 @@ class BlubberThread extends SimpleORMap implements PrivacyObject
     /**
      * @return BlubberThread[]
      */
-    public static function findBySQL($sql, $params = [])
+    public static function findBySQL($condition, $params = [])
     {
-        return parent::findAndMapBySQL(function ($thread) {
+        return parent::findAndMapBySQL(function (BlubberThread $thread) {
             return self::upgradeThread($thread);
-        }, $sql, $params);
+        }, $condition, $params);
     }
 
     /**
diff --git a/lib/models/OERHost.php b/lib/models/OERHost.php
index d0b1f6928a68fd0db5a5ae37e1929659679d232f..f4303e33f181a64c07f69fa89e49f74022ac9191 100644
--- a/lib/models/OERHost.php
+++ b/lib/models/OERHost.php
@@ -46,9 +46,9 @@ class OERHost extends OERIdentity
         ]);
     }
 
-    public static function findBySQL($sql, $params = [])
+    public static function findBySQL($condition, $params = [])
     {
-        $hosts = parent::findBySQL($sql, $params);
+        $hosts = parent::findBySQL($condition, $params);
         foreach ($hosts as $key => $host) {
             $class = $host['sorm_class'];
             if ($class && ($class !== 'OERHost') && is_subclass_of($class, 'OERHost')) {
diff --git a/lib/models/SimpleORMap.class.php b/lib/models/SimpleORMap.class.php
index 7af9dece8403d0177084cb8d8957e2af06813448..80925c32dada9a031d2e46dc6a2542223081b200 100644
--- a/lib/models/SimpleORMap.class.php
+++ b/lib/models/SimpleORMap.class.php
@@ -484,22 +484,29 @@ class SimpleORMap implements ArrayAccess, Countable, IteratorAggregate
     /**
      * returns number of records
      *
-     * @param ?string $sql sql clause to use on the right side of WHERE
-     * @param ?array $params params for query
+     * @param string $condition sql clause to use on the right side of WHERE
+     * @param array $params params for query
      * @return int
      */
-    public static function countBySql($sql = '1', $params = [])
+    public static function countBySql($condition = '1', $params = [])
     {
         $db_table = static::db_table();
-        $db = DBManager::get();
-        $has_join = stripos($sql, 'JOIN ');
+
+        $has_join = stripos($condition, 'JOIN ');
         if ($has_join === false || $has_join > 10) {
-            $sql = 'WHERE ' . $sql;
+            $sql = "SELECT COUNT(*) FROM `{$db_table}` WHERE {$condition}";
+        } else {
+            $pk = implode(',', array_map(
+                function ($key) use ($db_table) {
+                    return "`{$db_table}`.`{$key}`";
+                },
+                static::pk()
+            ));
+
+            $sql = "SELECT COUNT(DISTINCT {$pk}) FROM `{$db_table}` {$condition}";
         }
-        $sql = "SELECT count(*) FROM `" .  $db_table . "` " . $sql;
-        $st = $db->prepare($sql);
-        $st->execute($params);
-        return (int)$st->fetchColumn();
+
+        return (int) DBManager::get()->fetchColumn($sql, $params);
     }
 
     /**
@@ -608,26 +615,31 @@ class SimpleORMap implements ArrayAccess, Countable, IteratorAggregate
 
     /**
      * returns array of instances of given class filtered by given sql
-     * @param string $sql sql clause to use on the right side of WHERE
-     * @param ?array $params parameters for query
+     * @param string $condition sql clause to use on the right side of WHERE
+     * @param array $params parameters for query
      * @return array array of "self" objects
      */
-    public static function findBySQL($sql, $params = [])
+    public static function findBySQL($condition, $params = [])
     {
         $db_table = static::db_table();
-        $class = get_called_class();
-        $record = new $class();
-        $db = DBManager::get();
-        $has_join = stripos($sql, 'JOIN ');
+
+        $has_join = stripos($condition, 'JOIN ');
         if ($has_join === false || $has_join > 10) {
-            $sql = 'WHERE ' . $sql;
+            $condition = "WHERE {$condition}";
+            $distinct = '';
+        } else {
+            $distinct = 'DISTINCT';
         }
-        $sql = "SELECT `" . $db_table . "`.* FROM `" . $db_table . "` " . $sql;
-        $ret = [];
+        $sql = "SELECT {$distinct} `{$db_table}`.* FROM `{$db_table}` {$condition}";
+
+        $record = new static();
+        $record->setNew(false);
+
         $stmt = DBManager::get()->prepare($sql);
         $stmt->execute($params);
         $stmt->setFetchMode(PDO::FETCH_INTO , $record);
-        $record->setNew(false);
+
+        $ret = [];
         while ($record = $stmt->fetch()) {
             // Reset all relations
             $record->cleanup();
@@ -695,23 +707,27 @@ class SimpleORMap implements ArrayAccess, Countable, IteratorAggregate
      * passes objects for given sql through given callback
      *
      * @param callable $callable callback which gets the current record as param
-     * @param string $sql where clause of sql
+     * @param string $condition where clause of sql
      * @param ?array $params sql statement parameters
      * @return integer number of found records
      */
-    public static function findEachBySQL($callable, $sql, $params = [])
+    public static function findEachBySQL($callable, $condition, $params = [])
     {
-        $has_join = stripos($sql, 'JOIN ');
+        $db_table = static::db_table();
+
+        $has_join = stripos($condition, 'JOIN ');
         if ($has_join === false || $has_join > 10) {
-            $sql = "WHERE {$sql}";
+            $condition = "WHERE {$condition}";
+            $distinct = '';
+        } else {
+            $distinct = 'DISTINCT';
         }
+        $sql = "SELECT {$distinct} `{$db_table}`.* FROM `{$db_table}` {$condition}";
 
-        $class = get_called_class();
-        $record = new $class();
+        $record = new static();
         $record->setNew(false);
 
-        $db_table = static::db_table();
-        $st = DBManager::get()->prepare("SELECT `{$db_table}`.* FROM `{$db_table}` {$sql}");
+        $st = DBManager::get()->prepare($sql);
         $st->execute($params);
         $st->setFetchMode(PDO::FETCH_INTO , $record);