[CALCITE-2159] UNNEST to support 'ANY' type

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.17.0
• Assignee: Julian Hyde
• Reporter: Chunhui Shi
• Created: 30/Jan/18 20:56
• Updated: 20/Jul/18 08:18
• Resolved: 01/May/18 23:03

Description

Not all data source has type information about the input of UNNEST during parsing stage. In Drill, if we want to support UNNEST(table.column) syntax for a document with nested structure, for now, these two things will happen:

SqlUnnestOperator.inferReturnType will use unknown operand's type 'ANY' so isStruct will be false, thus the the following code will hit NULL reference.

 

Another issue is, Should UnnestnameSpace.getTable return a table so when other parts of the query tried to refer to some columns coming out of UNNEST, we know the query is asking for a column from the table, so the parser could add the column to the RowType of UNNEST? An example query is like this:

SELECT AVG(o.o_amount) AS avg_orders FROM  UNNEST(c.orders) AS o