[ https://issues.apache.org/jira/browse/TRAFODION-1673?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15359961#comment-15359961 ]
liu ming commented on TRAFODION-1673: ------------------------------------- It can be first implemented using sub-query, that is, to replace each WITH clause by a sub query. (RenamedTable) CTE mentioned by QiFan is a great idea, and we can set it as a final goal. To meet the functional requirement, we can simply use subquery in the first iteration. > Implement the WITH clause in Trafodion SQL for simple use cases > --------------------------------------------------------------- > > Key: TRAFODION-1673 > URL: https://issues.apache.org/jira/browse/TRAFODION-1673 > Project: Apache Trafodion > Issue Type: New Feature > Components: sql-cmp > Reporter: Hans Zeller > Assignee: liu ming > > We keep running into queries that use a WITH clause to define a temporary > view that can be used once or multiple times in a FROM clause in the query. > For non-recursive queries, the WITH clause could probably be handled very > similar to a view. When it is defined, we create an in-memory view > descriptor, containing the name and the definition. When it is used in a FROM > clause, we could go through a code path similar to that of a view - bind the > (temporary) view text and substitute it in the query. The fix could probably > be handled entirely in the binder. > This JIRA is *not* about recursive queries, those would require a lot more > effort, involving many components in addition to the binder. -- This message was sent by Atlassian JIRA (v6.3.4#6332)