function DatabaseSelectSubqueryTestCase::testFromSubquerySelect in Drupal 7

Test that we can use a subquery in a FROM clause.

File

modules/simpletest/tests/database_test.test, line 1743

Class

DatabaseSelectSubqueryTestCase

Test case for subselects in a dynamic SELECT query.

Code

function testFromSubquerySelect() {

  // Create a subquery, which is just a normal query object.
  $subquery = db_select('test_task', 'tt');
  $subquery
    ->addField('tt', 'pid', 'pid');
  $subquery
    ->addField('tt', 'task', 'task');
  $subquery
    ->condition('priority', 1);
  for ($i = 0; $i < 2; $i++) {

    // Create another query that joins against the virtual table resulting
    // from the subquery.
    $select = db_select($subquery, 'tt2');
    $select
      ->join('test', 't', 't.id=tt2.pid');
    $select
      ->addField('t', 'name');
    if ($i) {

      // Use a different number of conditions here to confuse the subquery
      // placeholder counter, testing http://drupal.org/node/1112854.
      $select
        ->condition('name', 'John');
    }
    $select
      ->condition('task', 'code');

    // The resulting query should be equivalent to:
    // SELECT t.name
    // FROM (SELECT tt.pid AS pid, tt.task AS task FROM test_task tt WHERE priority=1) tt
    //   INNER JOIN test t ON t.id=tt.pid
    // WHERE tt.task = 'code'
    $people = $select
      ->execute()
      ->fetchCol();
    $this
      ->assertEqual(count($people), 1, 'Returned the correct number of rows.');
  }
}