[CALCITE-1586] JDBC adapter generates wrong SQL if UNION has more than two inputs

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.10.0
• Fix Version/s: 1.12.0
• Component/s: jdbc-adapter

Environment

NA

• Assignee: Julian Hyde
• Reporter: Zhiqiang He
• Created: 18/Jan/17 03:51
• Updated: 24/Mar/17 03:20
• Resolved: 25/Jan/17 21:42

Description

JDBC adapter generates wrong SQL if set operation (UNION, INTERSECT or MINUS) has more than two inputs. In union example, after UnionMergeRule, the union input is convert to three input, and rel-to-sql convert result is wrong.

input sql

 SELECT *
FROM (SELECT \"product_id\"
FROM \"foodmart\".\"product\"
UNION ALL
SELECT \"product_id\"
FROM \"foodmart\".\"sales_fact_1997\")
UNION ALL
SELECT \"product_class_id\" AS \"PRODUCT_ID\"
FROM \"foodmart\".\"product_class\"
 

output sql

SELECT \"product_id\"
FROM \"foodmart\".\"product\"
UNION ALL
SELECT \"product_id\"
FROM \"foodmart\".\"sales_fact_1997\"
 

the last union query is lost.