abap：sort

sort a b descending 不能按照A B都降序排

Syntax

SORT itab [STABLE]
           { { [ASCENDING|DESCENDING]
               [AS TEXT]
             [BY { [ASCENDING|DESCENDING] [AS TEXT]}
                   { [ASCENDING|DESCENDING] [AS TEXT]}
                   ... ] }
           | { [BY (otab)] } }.