diff --git a/src/Adapter/Driver/Pdo/Result.php b/src/Adapter/Driver/Pdo/Result.php
index 6c55f7f6..54d37647 100644
--- a/src/Adapter/Driver/Pdo/Result.php
+++ b/src/Adapter/Driver/Pdo/Result.php
@@ -81,7 +81,7 @@ class Result implements Iterator, ResultInterface
     /** @var string|int|false|null */
     protected $generatedValue;
 
-    protected Closure|int $rowCount;
+    protected Closure|int|null $rowCount = null;
 
     /**
      * Initialize
@@ -91,7 +91,7 @@ class Result implements Iterator, ResultInterface
     public function initialize(
         PDOStatement $resource,
         $generatedValue,
-        Closure|int $rowCount = 0
+        Closure|int|null $rowCount = null
     ): ResultInterface&Result {
         $this->resource       = $resource;
         $this->generatedValue = $generatedValue;
@@ -250,7 +250,6 @@ public function count()
         if (is_int($this->rowCount)) {
             return $this->rowCount;
         }
-        /** @phpstan-ignore instanceof.alwaysTrue */
         if ($this->rowCount instanceof Closure) {
             $this->rowCount = (int) ($this->rowCount)();
         } else {
diff --git a/test/unit/Adapter/Driver/Pdo/ResultTest.php b/test/unit/Adapter/Driver/Pdo/ResultTest.php
index 85c38a9b..1044874a 100644
--- a/test/unit/Adapter/Driver/Pdo/ResultTest.php
+++ b/test/unit/Adapter/Driver/Pdo/ResultTest.php
@@ -17,6 +17,7 @@
 use function uniqid;
 
 #[CoversMethod(Result::class, 'current')]
+#[CoversMethod(Result::class, 'count')]
 #[Group('result-pdo')]
 final class ResultTest extends TestCase
 {
@@ -108,4 +109,74 @@ public function testMultipleRewind(): void
         $this->assertEquals(2, $position);
         $this->assertEquals($data[1], $result->current());
     }
+
+    public function testCountWithNoRowCountFallsBackToStatementRowCount(): void
+    {
+        $stub = $this->getMockBuilder(PDOStatement::class)->getMock();
+        $stub->expects($this->once())
+            ->method('rowCount')
+            ->willReturn(5);
+
+        $result = new Result();
+        $result->initialize($stub, null);
+
+        self::assertSame(5, $result->count());
+    }
+
+    public function testCountWithClosureInvokesClosureAndReturnsValue(): void
+    {
+        $stub = $this->getMockBuilder(PDOStatement::class)->getMock();
+        $stub->expects($this->never())->method('rowCount');
+
+        $rowCount = static fn(): int => 42;
+
+        $result = new Result();
+        $result->initialize($stub, null, $rowCount);
+
+        self::assertSame(42, $result->count());
+    }
+
+    public function testCountWithIntReturnsProvidedValue(): void
+    {
+        $stub = $this->getMockBuilder(PDOStatement::class)->getMock();
+        $stub->expects($this->never())->method('rowCount');
+
+        $result = new Result();
+        $result->initialize($stub, null, 10);
+
+        self::assertSame(10, $result->count());
+    }
+
+    public function testCountCachesResultFromClosure(): void
+    {
+        $callCount = 0;
+        $rowCount  = static function () use (&$callCount): int {
+            $callCount++;
+            return 7;
+        };
+
+        $stub = $this->getMockBuilder(PDOStatement::class)->getMock();
+
+        $result = new Result();
+        $result->initialize($stub, null, $rowCount);
+
+        $result->count();
+        $result->count();
+
+        self::assertSame(1, $callCount);
+    }
+
+    public function testCountCachesResultFromStatementRowCount(): void
+    {
+        $stub = $this->getMockBuilder(PDOStatement::class)->getMock();
+        $stub->expects($this->once())->method('rowCount')->willReturn(3);
+
+        $result = new Result();
+        $result->initialize($stub, null);
+
+        $result->count();
+        $result->count();
+
+        self::assertSame(3, $result->count());
+    }
 }