#define GREATEST(%a,%b) CASE WHEN %a > %b then %a else %b end

;вызов
&sql(declare c cursor for select $$$GREATEST(id, 8 ) from test.mytable for read only)
&sql(open c)
for  {
  &sql(fetch c into :res)
  q:SQLCODE
  w res,!
}
&sql(close c)

ClassMethod GREATEST(args... As %List) As %Integer [SqlProc, SqlName = GREATEST]
{
  set res= 0 
  for i= 1 : 1 :$GET(args,  0 ) set:$GET(args(i),  0 )>res res=$GET(args(i),  0 )
  q res
}

select test.GREATEST(id, 8 ) from test.mytable

select GREATEST( 2 , 1 , 7 , 0 ,,,,'78g',,, 5 ) from mytable