Fix invalid SQL generation with empty where groups

Author: JulianVennen

src/Query/Query.php

@@ -83,7 +83,7 @@ public function where(WhereCondition|array|WhereGroup $where): static
      */
     public function getWhere(): WhereGroup|null
     {
-        if ($this->where) {
+        if ($this->where && $this->where->count() > 0) {
             return $this->where;
         }
 
@@ -192,4 +192,4 @@ public function getLimit(): ?Limit
     {
         return $this->limit;
     }
-}
+}

test/tests/SQLTest.php

@@ -30,6 +30,16 @@ public function testSelect()
         $this->assertEquals("SELECT * FROM `test`", $this->sql->generate($query));
     }
 
+    public function testSelectEmptyWhere()
+    {
+        $query = new SelectQuery(
+            new WhereGroup(),
+        );
+        $query->modelClassName = TestModel::class;
+
+        $this->assertEquals("SELECT * FROM `test`", $this->sql->generate($query));
+    }
+
     public function testSelectWhereCondition()
     {
         $query = new SelectQuery(