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 ]