[HIVE-1070] CREATE VIEW followup: add support for column-aliasing on subselect and use it when storing view definition with column renaming

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.6.0
• Component/s: Query Processor
• Assignee: John Sichi
• Reporter: John Sichi
• Created: 20/Jan/10 22:04
• Updated: 16/Jun/10 02:00

Description

Copied from the original comment:

If you do CREATE VIEW v(x,y) AS SELECT a+1,b+2 FROM t

then we'll store the expanded view def as SELECT `_c0` AS `x`,`_c1` AS `y` FROM (SELECT `t`.`a`+1,`t`.`b`+2 FROM `t`) `v`

As a result, if hive ever changes its convention for generating anonymous expression names (_c0, _c1, ...), such stored view definitions will break.

The only way I can think of to avoid this is to implement SQL:200n's column-alias-by-position construct , e.g.

(SELECT `t`.`a`+1,`t`.`b`+2 FROM `t`) AS `v`(`x`,`y`)

(similar to what was done for LATERAL VIEW).

Issue Links

• relates to: HIVE-972 Support views