SORT path_expr ( REVERSE | ( [ REMOVE NULLS ] ORDER BY ( path_expr [ ASC | DESC ] ) [ , ( path_expr [ ASC | DESC ] ) ]... | [ ASC | DESC ] [ UNIQUE ] [ REMOVE NULLS ] ) ) [ { IGNORE | ERROR | NULL } ON MISSING ] [ { IGNORE | ERROR | NULL } ON MISMATCH ] [ { IGNORE | ERROR } ON EMPTY ] [ { IGNORE | ERROR } ON ERROR ]