{ expr
     { = | != | ^= | <> | > | < | >= | <= }
     { ANY | SOME | ALL }
     ({ expression_list | subquery })
| ( expr [, expr ]... )
  { = | != | ^= | <> }
  { ANY | SOME | ALL }
  ({ expression_list
     [, expression_list ]...
   | subquery
   }
  )
}