diff --git a/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php b/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php
index 3b67661c8b..46bb536dfd 100644
--- a/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php
+++ b/lib/private/DB/QueryBuilder/FunctionBuilder/FunctionBuilder.php
@@ -72,9 +72,10 @@ class FunctionBuilder implements IFunctionBuilder {
 		return new QueryFunction($this->helper->quoteColumnName($x) . ' - ' . $this->helper->quoteColumnName($y));
 	}
 
-	public function count($count, $alias = '') {
+	public function count($count = '', $alias = '') {
 		$alias = $alias ? (' AS ' . $this->helper->quoteColumnName($alias)) : '';
-		return new QueryFunction('COUNT(' . $this->helper->quoteColumnName($count) . ')' . $alias);
+		$quotedName = $count === '' ? '*' : $this->helper->quoteColumnName($count);
+		return new QueryFunction('COUNT(' . $quotedName . ')' . $alias);
 	}
 
 	public function max($field) {
diff --git a/lib/public/DB/QueryBuilder/IFunctionBuilder.php b/lib/public/DB/QueryBuilder/IFunctionBuilder.php
index 066be47015..861a576914 100644
--- a/lib/public/DB/QueryBuilder/IFunctionBuilder.php
+++ b/lib/public/DB/QueryBuilder/IFunctionBuilder.php
@@ -104,7 +104,7 @@ interface IFunctionBuilder {
 	 * @return IQueryFunction
 	 * @since 14.0.0
 	 */
-	public function count($count, $alias = '');
+	public function count($count = '', $alias = '');
 
 	/**
 	 * Takes the maximum of all rows in a column