[CALCITE-727] Constant folding involving CASE and NULL

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.4.0-incubating
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 14/May/15 17:54
• Updated: 01/Sep/15 03:02
• Resolved: 18/Jun/15 18:10

Description

There are a few Hive issues relating to constant reduction of NULL and CASE. Calcite should do the same.

HIVE-9645:

select count(1) from store_sales where null=1;
# should simplify to
select count(1) from store_sales where false;

HIVE-9644:

select count(1) from store_sales where (case ss_sold_date when '1998-01-01' then 1 else null end)=1;
# should simplify to
select count(1) from store_sales where ss_sold_date= '1998-01-01' ;

Issue Links

• is related to: HIVE-9645 Constant folding case NULL equality
• relates to: HIVE-9644 Fold case & when udfs