suibianwanwan created CALCITE-7010:
--------------------------------------
Summary: The well-known count bug
Key: CALCITE-7010
URL: https://issues.apache.org/jira/browse/CALCITE-7010
Project: Calcite
Issue Type: Bug
Reporter: suibianwanwan
What is the count-bug: [Optimization of Nested SQL Queries
Revisited|https://dl.acm.org/doi/pdf/10.1145/38714.38723]
{quote}The well-known "count-bug" is not specific to the count aggregate, and
outer-join does not solve it. The anomaly can occur on any aggregate function;
aggregates need modification to distiguish empty set from null values; and
optimizing out the outerjoin depends on utilization context
{quote}
Test in sub-query.iq:
{code:java}
SELECT deptno
FROM dept d
WHERE 0 IN (
SELECT COUNT(*)
FROM emp e
WHERE d.deptno = e.deptno
);
+--------+
| DEPTNO |
+--------+
| 40 |
+--------+
(1 row)
!ok
SELECT deptno
FROM dept d
WHERE 'Regular' IN (
SELECT CASE WHEN SUM(sal) > 10 then 'VIP' else 'Regular' END expr
FROM emp e
WHERE d.deptno = e.deptno
);
+--------+
| DEPTNO |
+--------+
| 40 |
+--------+
(1 row)
!ok
{code}
Actual results:
{code:java}
+--------+
| DEPTNO |
+--------+
+--------+
(0 rows)
+--------+
| DEPTNO |
+--------+
+--------+
(0 rows)
{code}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
