Sorts a table in descending order of specified columns. The sort is by the first column specified, then by the second column within the first, and so on.

x xdesc y    xdesc[x;y]

Where x is a symbol vector of column names defined in y, which is passed by

• value, returns
• reference, updates

y sorted in descending order by x.

The `s# attribute is not set. The sort is stable, i.e. it preserves order amongst equals.

q)\l sp.q
q)s
s | name  status city
--| -------------------
s1| smith 20     london
s2| jones 10     paris
s3| blake 30     paris
s4| clark 20     london
s5| adams 30     athens
q)`city xdesc s                 / sort descending by city
s | name  status city
--| -------------------
s2| jones 10     paris
s3| blake 30     paris
s1| smith 20     london
s4| clark 20     london
s5| adams 30     athens
q)meta `city xdesc s            / `s# attribute not set
c     | t f a
------| -----
s     | s
name  | s
status| i
city  | s

Duplicate column names xdesc signals dup if it finds duplicate columns in the right argument. (Since V3.6 2019.02.19.)