public Tables::addField($field, $type, $langcode)
Adds a field to a database query.
Parameters
string $field: If it doesn't contain a dot, then an entity base field name. If it contains a dot, then either field name dot field column or field name dot delta dot field column. Delta can be a numeric value or a "%delta" for any value.
string $type: Join type, can either be INNER or LEFT.
string $langcode: The language code the field values are to be queried in.
Return value
string The return valu