diff --git a/mailpoet/lib/Doctrine/WPDB/Connection.php b/mailpoet/lib/Doctrine/WPDB/Connection.php
index 11ac2eb534..a7e8e83074 100644
--- a/mailpoet/lib/Doctrine/WPDB/Connection.php
+++ b/mailpoet/lib/Doctrine/WPDB/Connection.php
@@ -25,7 +25,10 @@ class Connection implements ServerInfoAwareConnection {
   }
 
   public function query(string $sql): Result {
-    // TODO: Implement query() method.
+    global $wpdb;
+    $value = $this->runQuery($sql);
+    $result = $wpdb->last_result;
+    return new Result($result, is_int($value) ? $value : 0);
   }
 
   public function exec(string $sql): int {
diff --git a/mailpoet/lib/Doctrine/WPDB/Result.php b/mailpoet/lib/Doctrine/WPDB/Result.php
index 17e1d773f7..e11ec1f6ae 100644
--- a/mailpoet/lib/Doctrine/WPDB/Result.php
+++ b/mailpoet/lib/Doctrine/WPDB/Result.php
@@ -4,40 +4,69 @@ namespace MailPoet\Doctrine\WPDB;
 
 use MailPoetVendor\Doctrine\DBAL\Driver\Result as ResultInterface;
 
+/**
+ * WPDB fetches all results from the underlying database driver,
+ * so we need to implement the result methods on in-memory data.
+ */
 class Result implements ResultInterface {
+  /** @var array[] */
+  private array $result = [];
+  private int $rowCount;
+  private int $cursor = 0;
+
+  public function __construct(
+    array $result,
+    int $rowCount
+  ) {
+    foreach ($result as $value) {
+      $this->result[] = (array)$value;
+    }
+    $this->rowCount = $rowCount;
+  }
+
   public function fetchNumeric() {
-    // TODO: Implement fetchNumeric() method.
+    $value = $this->result[$this->cursor++] ?? null;
+    return $value === null ? false : array_values($value);
   }
 
   public function fetchAssociative() {
-    // TODO: Implement fetchAssociative() method.
+    return $this->result[$this->cursor++] ?? false;
   }
 
   public function fetchOne() {
-    // TODO: Implement fetchOne() method.
+    $value = $this->result[$this->cursor++] ?? null;
+    return $value === null ? false : reset($value);
   }
 
   public function fetchAllNumeric(): array {
-    // TODO: Implement fetchAllNumeric() method.
+    $result = [];
+    foreach ($this->result as $value) {
+      $result[] = array_values($value);
+    }
+    return $result;
   }
 
   public function fetchAllAssociative(): array {
-    // TODO: Implement fetchAllAssociative() method.
+    return $this->result;
   }
 
   public function fetchFirstColumn(): array {
-    // TODO: Implement fetchFirstColumn() method.
+    $result = [];
+    foreach ($this->result as $value) {
+      $result[] = reset($value);
+    }
+    return $result;
   }
 
   public function rowCount(): int {
-    // TODO: Implement rowCount() method.
+    return $this->rowCount;
   }
 
   public function columnCount(): int {
-    // TODO: Implement columnCount() method.
+    return count($this->result[0] ?? []);
   }
 
   public function free(): void {
-    // TODO: Implement free() method.
+    $this->cursor = 0;
   }
 }
diff --git a/mailpoet/tests/integration/Doctrine/WPDB/ConnectionTest.php b/mailpoet/tests/integration/Doctrine/WPDB/ConnectionTest.php
index 9cfe8502a7..70ede27985 100644
--- a/mailpoet/tests/integration/Doctrine/WPDB/ConnectionTest.php
+++ b/mailpoet/tests/integration/Doctrine/WPDB/ConnectionTest.php
@@ -3,6 +3,7 @@
 namespace MailPoet\Test\Doctrine\WPDB;
 
 use MailPoet\Doctrine\WPDB\Connection;
+use MailPoet\Doctrine\WPDB\Result;
 use MailPoetTest;
 use mysqli;
 
@@ -24,6 +25,30 @@ class ConnectionTest extends MailPoetTest {
     $this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
   }
 
+  public function testQuery(): void {
+    $connection = new Connection();
+
+    // select
+    $result = $connection->query('SELECT 123');
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame('123', $result->fetchOne());
+
+    // insert
+    $result = $connection->query(sprintf("INSERT INTO %s (value) VALUES ('test')", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertFalse($result->fetchOne());
+
+    // update
+    $result = $connection->query(sprintf("UPDATE %s SET value = 'updated' WHERE id = %d", self::TEST_TABLE_NAME, $connection->lastInsertId()));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertFalse($result->fetchOne());
+
+    // delete
+    $result = $connection->query(sprintf("DELETE FROM %s WHERE id = %d", self::TEST_TABLE_NAME, $connection->lastInsertId()));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertFalse($result->fetchOne());
+  }
+
   public function testExec(): void {
     $connection = new Connection();
 
diff --git a/mailpoet/tests/integration/Doctrine/WPDB/ResultTest.php b/mailpoet/tests/integration/Doctrine/WPDB/ResultTest.php
new file mode 100644
index 0000000000..daf9162203
--- /dev/null
+++ b/mailpoet/tests/integration/Doctrine/WPDB/ResultTest.php
@@ -0,0 +1,165 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Test\Doctrine\WPDB;
+
+use MailPoet\Doctrine\WPDB\Connection;
+use MailPoet\Doctrine\WPDB\Result;
+use MailPoetTest;
+
+class ResultTest extends MailPoetTest {
+  private const TEST_TABLE_NAME = 'doctrine_wpdb_result_test';
+
+  public function _before() {
+    parent::_before();
+    $connection = new Connection();
+    $connection->exec(sprintf('DROP TABLE IF EXISTS %s', self::TEST_TABLE_NAME));
+    $connection->exec(sprintf('
+      CREATE TABLE %s (
+        id int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
+        value varchar(255) NOT NULL)
+    ', self::TEST_TABLE_NAME));
+  }
+
+  public function testInsert(): void {
+    $connection = new Connection();
+    $result = $connection->query(sprintf("INSERT INTO %s (value) VALUES ('test')", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame(1, $result->rowCount());
+    $this->assertSame(0, $result->columnCount());
+    $this->assertSame([], $result->fetchAllAssociative());
+  }
+
+  public function testUpdate(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('test')", self::TEST_TABLE_NAME));
+    $result = $connection->query(sprintf("UPDATE %s SET value = 'updated' WHERE id = %d", self::TEST_TABLE_NAME, $connection->lastInsertId()));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame(1, $result->rowCount());
+    $this->assertSame(0, $result->columnCount());
+    $this->assertSame([], $result->fetchAllAssociative());
+  }
+
+  public function testFetchNumeric(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame(['1', 'aaa'], $result->fetchNumeric());
+    $this->assertSame(['2', 'bbb'], $result->fetchNumeric());
+    $this->assertSame(['3', 'ccc'], $result->fetchNumeric());
+    $this->assertFalse($result->fetchNumeric());
+  }
+
+  public function testFetchAssociative(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame(['id' => '1', 'value' => 'aaa'], $result->fetchAssociative());
+    $this->assertSame(['id' => '2', 'value' => 'bbb'], $result->fetchAssociative());
+    $this->assertSame(['id' => '3', 'value' => 'ccc'], $result->fetchAssociative());
+    $this->assertFalse($result->fetchAssociative());
+  }
+
+  public function testFetchOne(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame('1', $result->fetchOne());
+    $this->assertSame('2', $result->fetchOne());
+    $this->assertSame('3', $result->fetchOne());
+    $this->assertFalse($result->fetchOne());
+  }
+
+  public function testFetchAllNumeric(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame([['1', 'aaa'], ['2', 'bbb'], ['3', 'ccc']], $result->fetchAllNumeric());
+  }
+
+  public function testFetchAllAssociative(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame([
+      ['id' => '1', 'value' => 'aaa'],
+      ['id' => '2', 'value' => 'bbb'],
+      ['id' => '3', 'value' => 'ccc'],
+    ], $result->fetchAllAssociative());
+  }
+
+  public function testFetchFirstColumn(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame(['1', '2', '3'], $result->fetchFirstColumn());
+  }
+
+  public function testRowCount(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame(3, $result->rowCount());
+  }
+
+  public function testColumnCount(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame(2, $result->columnCount());
+  }
+
+  public function testFree(): void {
+    $connection = new Connection();
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('aaa')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('bbb')", self::TEST_TABLE_NAME));
+    $connection->query(sprintf("INSERT INTO %s (value) VALUES ('ccc')", self::TEST_TABLE_NAME));
+
+    $result = $connection->query(sprintf("SELECT * FROM %s", self::TEST_TABLE_NAME));
+    $this->assertInstanceOf(Result::class, $result);
+    $this->assertSame('1', $result->fetchOne());
+    $this->assertSame('2', $result->fetchOne());
+    $this->assertSame('3', $result->fetchOne());
+    $this->assertFalse($result->fetchOne());
+
+    $result->free();
+    $this->assertSame('1', $result->fetchOne());
+  }
+
+  public function _after() {
+    parent::_after();
+    $connection = new Connection();
+    $connection->exec(sprintf('DROP TABLE IF EXISTS %s', self::TEST_TABLE_NAME));
+  }
+}
diff --git a/mailpoet/tests/unit/Doctrine/WPDB/ResultTest.php b/mailpoet/tests/unit/Doctrine/WPDB/ResultTest.php
new file mode 100644
index 0000000000..f6f73035cd
--- /dev/null
+++ b/mailpoet/tests/unit/Doctrine/WPDB/ResultTest.php
@@ -0,0 +1,107 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Doctrine\WPDB;
+
+use MailPoetUnitTest;
+
+class ResultTest extends MailPoetUnitTest {
+  /** @var object[] */
+  private array $data;
+
+  public function _before() {
+    parent::_before();
+    $this->data = [
+      (object)['id' => '1', 'value' => 'aaa'],
+      (object)['id' => '2', 'value' => 'bbb'],
+      (object)['id' => '3', 'value' => 'ccc'],
+    ];
+  }
+
+  public function testFetchNumeric(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame(['1', 'aaa'], $result->fetchNumeric());
+    $this->assertSame(['2', 'bbb'], $result->fetchNumeric());
+    $this->assertSame(['3', 'ccc'], $result->fetchNumeric());
+    $this->assertSame(false, $result->fetchNumeric());
+
+    $result = new Result([], 0);
+    $this->assertSame(false, $result->fetchNumeric());
+  }
+
+  public function testFetchAssociative(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame(['id' => '1', 'value' => 'aaa'], $result->fetchAssociative());
+    $this->assertSame(['id' => '2', 'value' => 'bbb'], $result->fetchAssociative());
+    $this->assertSame(['id' => '3', 'value' => 'ccc'], $result->fetchAssociative());
+    $this->assertSame(false, $result->fetchAssociative());
+
+    $result = new Result([], 0);
+    $this->assertSame(false, $result->fetchAssociative());
+  }
+
+  public function testFetchOne(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame('1', $result->fetchOne());
+    $this->assertSame('2', $result->fetchOne());
+    $this->assertSame('3', $result->fetchOne());
+    $this->assertSame(false, $result->fetchOne());
+
+    $result = new Result([], 0);
+    $this->assertSame(false, $result->fetchOne());
+  }
+
+  public function testFetchAllNumeric(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame([['1', 'aaa'], ['2', 'bbb'], ['3', 'ccc']], $result->fetchAllNumeric());
+
+    $result = new Result([], 0);
+    $this->assertSame([], $result->fetchAllNumeric());
+  }
+
+  public function testFetchAllAssociative(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame([
+      ['id' => '1', 'value' => 'aaa'],
+      ['id' => '2', 'value' => 'bbb'],
+      ['id' => '3', 'value' => 'ccc'],
+    ], $result->fetchAllAssociative());
+
+    $result = new Result([], 0);
+    $this->assertSame([], $result->fetchAllAssociative());
+  }
+
+  public function testFetchFirstColumn(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame(['1', '2', '3'], $result->fetchFirstColumn());
+
+    $result = new Result([], 0);
+    $this->assertSame([], $result->fetchFirstColumn());
+  }
+
+  public function testRowCount(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame(2, $result->rowCount());
+
+    $result = new Result([], 0);
+    $this->assertSame(0, $result->rowCount());
+  }
+
+  public function testColumnCount(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame(2, $result->columnCount());
+
+    $result = new Result([], 0);
+    $this->assertSame(0, $result->columnCount());
+  }
+
+  public function testFree(): void {
+    $result = new Result($this->data, 2);
+    $this->assertSame('1', $result->fetchOne());
+    $this->assertSame('2', $result->fetchOne());
+    $this->assertSame('3', $result->fetchOne());
+    $this->assertSame(false, $result->fetchOne());
+
+    $result->free();
+    $this->assertSame('1', $result->fetchOne());
+  }
+}