function SelectSubqueryTest::testFromSubquerySelectWithLimit

Tests that we can use a subquery in a FROM clause with a LIMIT.

File

core/tests/Drupal/KernelTests/Core/Database/SelectSubqueryTest.php, line 53

Class

SelectSubqueryTest

Tests the Select query builder.

Namespace

Code

public function testFromSubquerySelectWithLimit() : void {
    // Create a subquery, which is just a normal query object.
    $subquery = $this->connection
        ->select('test_task', 'tt');
    $subquery->addField('tt', 'pid', 'pid');
    $subquery->addField('tt', 'task', 'task');
    $subquery->orderBy('priority', 'DESC');
    $subquery->range(0, 1);
    // Create another query that joins against the virtual table resulting
    // from the subquery.
    $select = $this->connection
        ->select($subquery, 'tt2');
    $select->join('test', 't', '[t].[id] = [tt2].[pid]');
    $select->addField('t', 'name');
    // The resulting query should be equivalent to:
    // @code
    // SELECT t.name
    // FROM (SELECT tt.pid AS pid, tt.task AS task FROM test_task tt ORDER BY priority DESC LIMIT 1 OFFSET 0) tt
    //   INNER JOIN test t ON t.id=tt.pid
    // @endcode
    $people = $select->execute()
        ->fetchCol();
    $this->assertCount(1, $people, 'Returned the correct number of rows.');
}