Fixed regression: PDO::FETCH_COLUMN was declared an unsupported fetch type

src/Adapter/Driver/Pdo/Result.php

@@ -38,7 +38,7 @@ class Result implements Iterator, ResultInterface
         PDO::FETCH_BOTH, // 4
         PDO::FETCH_OBJ, // 5
         PDO::FETCH_BOUND, // 6
-        // \PDO::FETCH_COLUMN,  // 7 (not a valid fetch mode)
+        PDO::FETCH_COLUMN,  // 7 (not a valid fetch mode)
         PDO::FETCH_CLASS, // 8
         PDO::FETCH_INTO, // 9
         PDO::FETCH_FUNC, // 10

test/integration/Adapter/Driver/Pdo/Mysql/TableGatewayTest.php

@@ -6,6 +6,7 @@
 use Laminas\Db\TableGateway\Feature\MetadataFeature;
 use Laminas\Db\TableGateway\TableGateway;
 use PHPUnit\Framework\TestCase;
+use Laminas\Db\Sql\Select;
 
 use function count;
 
@@ -38,6 +39,28 @@ public function testSelect()
         }
     }
 
+    /**
+     * @covers \Laminas\Db\TableGateway\TableGateway::select
+     */
+    public function testSelectFetchColumn()
+    {
+        $tableGateway = new TableGateway('test', $this->adapter);
+
+        $select = new Select();
+        $select->from('test');
+        $select->columns([
+            'myid' => 'id'
+        ]);
+        $select->limit(1);
+
+        $statement = $tableGateway->getSql()
+            ->prepareStatementForSqlObject($select);
+
+        $result = $statement->execute();
+        $result->setFetchMode(\PDO::FETCH_COLUMN);
+        $this->assertSame('1', $result->next());
+    }
+
     /**
      * @covers \Laminas\Db\TableGateway\TableGateway::insert
      * @covers \Laminas\Db\TableGateway\TableGateway::select

test/integration/Adapter/Driver/Pdo/Postgresql/TableGatewayTest.php

@@ -7,6 +7,7 @@
 use Laminas\Db\TableGateway\Feature\SequenceFeature;
 use Laminas\Db\TableGateway\TableGateway;
 use PHPUnit\Framework\TestCase;
+use Laminas\Db\Sql\Select;
 
 class TableGatewayTest extends TestCase
 {
@@ -26,4 +27,26 @@ public function testLastInsertValue()
         $tableGateway->insert(['foo' => 'baz']);
         self::assertSame(2, $tableGateway->getLastInsertValue());
     }
+
+    /**
+     * @covers \Laminas\Db\TableGateway\TableGateway::select
+     */
+    public function testSelectFetchColumn()
+    {
+        $tableGateway = new TableGateway('test', $this->adapter);
+
+        $select = new Select();
+        $select->from('test');
+        $select->columns([
+            'myid' => 'id'
+        ]);
+        $select->limit(1);
+
+        $statement = $tableGateway->getSql()
+            ->prepareStatementForSqlObject($select);
+
+        $result = $statement->execute();
+        $result->setFetchMode(\PDO::FETCH_COLUMN);
+        $this->assertSame(1, $result->next());
+    }
 }

test/unit/Adapter/Driver/Pdo/ResultTest.php

@@ -80,4 +80,19 @@ public function testFetchModeRange()
         self::assertEquals(11, $result->getFetchMode());
         self::assertInstanceOf('stdClass', $result->current());
     }
+
+    public function testFetchModeColumn()
+    {
+        $stub = $this->getMockBuilder('PDOStatement')->getMock();
+        $stub->expects($this->any())
+            ->method('fetch')
+            ->will($this->returnCallback(function () {
+                return 'column_value';
+            }));
+        $result = new Result();
+        $result->initialize($stub, null);
+        $result->setFetchMode(PDO::FETCH_COLUMN);
+        self::assertEquals(7, $result->getFetchMode());
+        self::assertSame('column_value', $result->current());
+    }
 }