diff --git a/lib/Misc/QueryFilter.php b/lib/Misc/QueryFilter.php
index f4a663d..f099487 100644
--- a/lib/Misc/QueryFilter.php
+++ b/lib/Misc/QueryFilter.php
@@ -13,8 +13,7 @@ class QueryFilter {
     protected $qWhereNot = []; // WHERE NOT clause components
     protected $tWhereNot = []; // WHERE NOT clause type bindings
     protected $vWhereNot = []; // WHERE NOT clause binding values
-
-    public $filterRestrictive = true;
+    protected $filterRestrictive = true; // Whether to glue WHERE conditions with OR (false) or AND (true)
 
     public function setWhere(string $where, $types = null, $values = null): static {
         $this->qWhere[] = $where;
@@ -34,13 +33,18 @@ class QueryFilter {
         return $this;
     }
 
-    public function setFilter(self $filter): static {
+    public function setWhereGroup(self $filter): static {
         $this->qWhere[] = "(".$filter->buildWhereBody().")";
         $this->tWhere[] = $filter->getWhereTypes();
         $this->vWhere[] = $filter->getWhereValues();
         return $this;
     }
 
+    public function setWhereRestrictive(bool $restrictive): static {
+        $this->filterRestrictive = $restrictive;
+        return $this;
+    }
+
     protected function getWhereTypes(): array {
         return ValueInfo::flatten([$this->tWhere, $this->tWhereNot]);
     }
diff --git a/tests/cases/Misc/TestQuery.php b/tests/cases/Misc/TestQuery.php
index f78ac2d..e638d76 100644
--- a/tests/cases/Misc/TestQuery.php
+++ b/tests/cases/Misc/TestQuery.php
@@ -7,6 +7,7 @@ declare(strict_types=1);
 namespace JKingWeb\Arsse\TestCase\Misc;
 
 use JKingWeb\Arsse\Misc\Query;
+use JKingWeb\Arsse\Misc\QueryFilter;
 
 /** 
  * @covers \JKingWeb\Arsse\Misc\Query
@@ -91,4 +92,24 @@ class TestQuery extends \JKingWeb\Arsse\Test\AbstractTest {
         $this->assertSame(["datetime", "str", "bool"], $q->getTypes());
         $this->assertSame([1, 3, 2], $q->getValues());
     }
-}
+
+    public function testNestedWhereConditions(): void {
+        $q = new Query("SELECT *, ? as const from table", "datetime", 1);
+        $f = new QueryFilter;
+        $f->setWhere("a = ?", "str", "ook")->setWhere("b = c")->setWhere("c = ?", "int", 42);
+        $this->assertSame("a = ? AND b = c AND c = ?", (string) $f);
+        $this->assertSame(["str", "int"], $f->getTypes());
+        $this->assertSame(["ook", 42], $f->getValues());
+        $q->setWhereGroup($f);
+        $f->setWhereRestrictive(false);
+        $this->assertSame("a = ? OR b = c OR c = ?", (string) $f);
+        $q->setWhereGroup($f);
+        $this->assertSame("SELECT *, ? as const from table WHERE (a = ? AND b = c AND c = ?) AND (a = ? OR b = c OR c = ?)", $q->getQuery());
+        $this->assertSame(["datetime", "str", "int", "str", "int"], $q->getTypes());
+        $this->assertSame([1, "ook", 42, "ook", 42], $q->getValues());
+        $q->setWhereRestrictive(false);
+        $this->assertSame("SELECT *, ? as const from table WHERE (a = ? AND b = c AND c = ?) OR (a = ? OR b = c OR c = ?)", $q->getQuery());
+        $this->assertSame(["datetime", "str", "int", "str", "int"], $q->getTypes());
+        $this->assertSame([1, "ook", 42, "ook", 42], $q->getValues());
+    }
+}
\ No newline at end of file