select sum((select count(*) from srv zt, z where  zt.some_id = z.sid
             union select count(*) from srv_arc yt, z where
yt.some_id = zsid))
 from  systables where tabid=1
#                                              ^
#  284: A subquery has returned not exactly one row.
#

Any suggestions on how to get this into the singleton select pls.

Its part of a huge support type corruption detction statement, so the
" into temp " is not an option.

Table z has a couple of integers as a list of jobs to investigate.