diff --git a/config/packages/doctrine.yaml b/config/packages/doctrine.yaml
index ffcafbabdb..a23e6838d4 100644
--- a/config/packages/doctrine.yaml
+++ b/config/packages/doctrine.yaml
@@ -95,5 +95,6 @@ doctrine:
         dql:
             datetime_functions:
                 datediff: App\Doctrine\Functions\DateDiff
+                timestampdiff: App\Doctrine\Functions\TimestampDiff
                 yearweek: App\Doctrine\Functions\YearWeek
                 geodistance: App\Doctrine\Functions\GeoDistance
diff --git a/src/Doctrine/Functions/TimestampDiff.php b/src/Doctrine/Functions/TimestampDiff.php
new file mode 100644
index 0000000000..728d3f4289
--- /dev/null
+++ b/src/Doctrine/Functions/TimestampDiff.php
@@ -0,0 +1,61 @@
+<?php
+
+namespace App\Doctrine\Functions;
+
+use Doctrine\ORM\Query\AST\Functions\FunctionNode;
+use Doctrine\ORM\Query\AST\Node;
+use Doctrine\ORM\Query\Lexer;
+use Doctrine\ORM\Query\Parser;
+use Doctrine\ORM\Query\SqlWalker;
+
+/**
+ * TimestampDiffFunction ::= 
+ *     "TIMESTAMPDIFF" "(" ArithmeticPrimary Identifier "," ArithmeticPrimary "," ArithmeticPrimary ")".
+ */
+class TimestampDiff extends FunctionNode
+{
+    /**
+     * @var string|null
+     */
+    public $unit = null;
+
+    /**
+     * @var Node|null
+     */
+    public $firstDatetimeExpression = null;
+
+    /**
+     * @var Node|null
+     */
+    public $secondDatetimeExpression = null;
+
+    public function parse(Parser $parser)
+    {
+        $parser->match(Lexer::T_IDENTIFIER);
+        $parser->match(Lexer::T_OPEN_PARENTHESIS);
+        $parser->match(Lexer::T_IDENTIFIER);
+        
+        /** @var Lexer $lexer */
+        $lexer = $parser->getLexer();
+        $this->unit = $lexer->token['value'];
+
+        $parser->match(Lexer::T_COMMA);
+
+        $this->firstDatetimeExpression = $parser->ArithmeticPrimary();
+
+        $parser->match(Lexer::T_COMMA);
+
+        $this->secondDatetimeExpression = $parser->ArithmeticPrimary();
+
+        $parser->match(Lexer::T_CLOSE_PARENTHESIS);
+    }
+
+    public function getSql(SqlWalker $sqlWalker)
+    {
+        return 'TIMESTAMPDIFF(' .
+            $this->unit . ', ' .
+            $this->firstDatetimeExpression->dispatch($sqlWalker) . ', ' .
+            $this->secondDatetimeExpression->dispatch($sqlWalker) .
+            ')';
+    }
+}
diff --git a/src/Repository/ActivityRepository.php b/src/Repository/ActivityRepository.php
index 7b6228f557..75acbb0cc3 100644
--- a/src/Repository/ActivityRepository.php
+++ b/src/Repository/ActivityRepository.php
@@ -76,7 +76,7 @@ public function queryProblematicActivities()
             ->join('App:ActivityAttendee', 'aa', Join::WITH, 'aa.activity = a and aa.organizer = 1')
             ->join('App:Member', 'm', Join::WITH, 'aa.attendee = m')
             ->where("m.status = 'Banned'")
-            ->orWhere('DATEDIFF(a.ends, a.starts) > 1')
+            ->orWhere('TIMESTAMPDIFF(MINUTE, a.starts, a.ends) >= 0')
             ->orderBy('a.id', 'desc')
             ->getQuery();
     }