JOIN support

[bggardner]

The Google Visualization Query language does not support JOINs, and I am not currently planning to implement JOINs in google-visualization-php. However, JOINs can be accomplished with a little more leg work using one of these work-arounds:

• Server-side in SQL:
  • Create a SQL View that performs any necessary JOIN(s) and pass the name of the view to xxxDataSourceHelper instead of a table name.

    CREATE VIEW `report` AS SELECT * FROM `scores` JOIN `people` ON `scores`.`person` = `people`.`id`

• Server-side in PHP:
  • Execute the JOIN in SQL, then apply the Google Query to the entire data set.

public function generateDataTable(Google\Visualization\DataSource\Query $query)
{
  $pdo = new PDO("mysql:host=xxx;port=xxx;dbname=xxx", "username", "password");
  $stmt = $pdo->query("SELECT * FROM `table1` JOIN `table2` ON `table1`.`col` = `table2`.`col`");
  $dataTable = Google\Visualization\DataSource\Util\Pdo\MySqlPdoDataSourceHelper::buildTable($stmt);
  return Google\Visualization\DataSource\DataSourceHelper::applyQuery($query, $dataTable, Locale::getDefault());
}

• Client-side in JavaScript:
  • Execute a query for each table involved in the JOIN and use google.visualization.data.join() to perform the desired JOIN(s).