[IMPALA-2677] QGen: Allow references to ancestor aliases in inline views

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: Impala 2.3.0
• Component/s: Infrastructure
• Labels: query_generator_development
• Target Version: Product Backlog
• Assignee: Unassigned
• Reporter: Taras Bobrovytsky
• Created: 18/Nov/15 01:59
• Updated: 28/Sep/17 19:50

Description

SELECT
  ...
FROM 
  customer t1
  INNER JOIN (
    SELECT 
      1
    FROM
      t1.c_orders t2 INNER JOIN customer t10 ON (...)
      INNER JOIN (
        SELECT
          1
        FROM 
          t2.o_lineitems t5 INNER JOIN t1.c_orders t6 ON (...)
       ) as INLINE_VIEW_A
  ) as INLINE_VIEW_B

The elements in the from clause of INLINE_VIEW_A can either be all uncorrelated collections or tables (like customer.c_orders, or part). or they call all be correlated collections from the parent's from clause (like t2.lineitems, or t10.orders). However, elements from ancestor's from clauses (like t1.orders) would never be referenced.