[CALCITE-4251] Get the origin column, even if it is derived

• Type: Wish
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.27.0
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: xzh_dz
• Created: 12/Sep/20 08:24
• Updated: 03/Jun/21 22:31
• Resolved: 18/Nov/20 11:51

Description

A case:

final String sql1 = ""
    + "select empno, sum(sal) as all_sal\n"
    + "from emp\n"
    + "group by empno";

When i try to get the `all_sal` origin column field,it will return null and it is derived. we always get the origin column although it is derived. We should overload this method and determine whether the column is derived by setting parameters.

 org.apache.calcite.rel.metadata.RelMetadataQuery#getColumnOrigin

// code placeholder
public RelColumnOrigin getColumnOrigin(RelNode rel, int column) {
  final Set<RelColumnOrigin> origins = getColumnOrigins(rel, column);
  if (origins == null || origins.size() != 1) {
    return null;
  }
  final RelColumnOrigin origin = Iterables.getOnlyElement(origins);
  return origin.isDerived() ? null : origin;
}

 

 

 

 

Issue Links

• links to: GitHub Pull Request #2189