The identifier of the query placeholder this condition has been compiled against. File core/lib/Drup

public Truncate::compile(Connection $connection, PlaceholderInterface $

public Query::__construct(Connection $connection, $options)

public ConditionInterface::exists(SelectInterface $select)

public Select::execute() Runs the query

public Query::uniqueIdentifier() Returns

public Select::groupBy($field) Groups

public SelectInterface::getArguments(PlaceholderInterface

public QueryConditionTrait::where($snippet, $args

The placeholder counter. File core/lib/Drupal/Core/Database/Query/SelectExtender.php, line 34