Select operator

The select operator restricts the stream of rows to only contain the variables specified.

Syntax

select <var> [ , <var> ... ];

Example

Schema for the following examples

#!test[schema, commit]
define
  entity content owns id;
  entity page sub content,
    owns page-id,
    owns name;
  entity profile sub page,
    owns username;
  entity user sub profile,
    owns phone,
    owns karma;

  attribute id value string;
  attribute page-id sub id;
  attribute username sub page-id;
  attribute name value string;
  attribute phone value string;
  attribute karma value double;
attribute group-id sub id;
attribute rank, value string @values("admin", "member");
attribute tag value string;
relation group-membership, relates group, relates member,  owns rank;
entity group, owns name, owns group-id, owns tag, plays group-membership:group;
user, plays group-membership:member;

#!test[read]
match
  $group isa group, has group-id "<group id>";
  group-membership (group: $group, member: $member), has rank "member";
select $member;