/**
* Select the given field expressions.
*
* @param $fieldExpression String The field to select (escaped SQL statement)
* @param $alias String The alias of that field (escaped SQL statement)
*/
public function selectField($fieldExpression, $alias = null)
{
$this->query->selectField($fieldExpression, $alias);
}
/**
* Invoked prior to getFinalisedQuery()
*
* @param DataQuery $dataQuery
* @param array $queriedColumns
* @param SQLSelect $sqlSelect
*/
public function beforeGetFinalisedQuery(DataQuery $dataQuery, $queriedColumns = [], SQLSelect $sqlSelect)
{
// Get metadata and SQL from join table
$hasManyRelation = $this->getParentRelationship($dataQuery);
$joinTableSQLSelect = $hasManyRelation->dataQuery()->query();
$joinTableSQL = $joinTableSQLSelect->sql($joinTableParameters);
$joinTableColumns = array_keys($joinTableSQLSelect->getSelect());
// Get aliases (keys) only
$joinTableAlias = $this->getJoinAlias();
// Get fields to join on
$localKey = $this->getLocalKey();
$schema = DataObject::getSchema();
$baseTable = $schema->baseDataClass($dataQuery->dataClass());
$childField = $schema->sqlColumnForField($baseTable, 'ID');
// Add select fields
foreach ($joinTableColumns as $joinTableColumn) {
$sqlSelect->selectField("\"{$joinTableAlias}\".\"{$joinTableColumn}\"", "{$joinTableAlias}_{$joinTableColumn}");
}
// Apply join and record sql for later insertion (at end of replacements)
$sqlSelect->addInnerJoin('(SELECT $$_SUBQUERY_$$)', "\"{$joinTableAlias}\".\"{$localKey}\" = {$childField}", $joinTableAlias, 20, $joinTableParameters);
$dataQuery->setQueryParam('Foreign.JoinTableSQL', $joinTableSQL);
// After this join, and prior to afterGetFinalisedQuery, $sqlSelect will be populated with the
// necessary sql rewrites (versioned, etc) that effect the base table.
// By using a placeholder for the subquery we can protect the subquery (already rewritten)
// from being re-written a second time. However we DO want the join predicate (above) to be rewritten.
// See http://php.net/manual/en/function.str-replace.php#refsect1-function.str-replace-notes
// for the reason we only add the final substitution at the end of getFinalisedQuery()
}