Issue #2795967 by daffie, Katiemouse: A query with a...

Issue #2795967 by daffie, Katiemouse: A query with a fetchAll(\PDO::FETCH_COLUMN) will fail for SQLite

core/lib/Drupal/Core/Database/StatementPrefetch.php

@@ -306,7 +306,7 @@ public function current() {
           return $this->fetchOptions['object'];
         case \PDO::FETCH_COLUMN:
           if (isset($this->columnNames[$this->fetchOptions['column']])) {
-            return $this->currentRow[$k][$this->columnNames[$this->fetchOptions['column']]];
+            return $this->currentRow[$this->columnNames[$this->fetchOptions['column']]];
           }
           else {
             return;

core/tests/Drupal/KernelTests/Core/Database/FetchTest.php

@@ -113,6 +113,19 @@ function testQueryFetchBoth() {
     $this->assertIdentical(count($records), 1, 'There is only one record.');
   }
 
+  /**
+   * Confirms that we can fetch all records into an array explicitly.
+   */
+  public function testQueryFetchAllColumn() {
+    $query = db_select('test');
+    $query->addField('test', 'name');
+    $query->orderBy('name');
+    $query_result = $query->execute()->fetchAll(\PDO::FETCH_COLUMN);
+
+    $expected_result = ['George', 'John', 'Paul', 'Ringo'];
+    $this->assertEqual($query_result, $expected_result, 'Returned the correct result.');
+  }
+
   /**
    * Confirms that we can fetch an entire column of a result set at once.
    */