[CALCITE-252] Scalar sub-query that returns 0 rows should become NULL value

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Labels: github-import
• Assignee: Unassigned
• Reporter: GitHub Import
• Created: 18/Jun/14 08:50
• Updated: 18/Jun/14 08:51
• Resolved: 18/Jun/14 08:51

Description

A scalar sub-query that returns 0 rows should become a NULL value. Currently it removes the whole row. For example,

```sql
select ename, deptno, (select name from dept where deptno = emp.deptno)
from emp
```

should return a row 'Fred, 20, null' but that row is missing.

The problem is that scalar sub-query is translated to a left join, and left join is incorrectly implemented as inner join.

---------------- Imported from GitHub ----------------
Url: https://github.com/julianhyde/optiq/issues/252
Created by: julianhyde
Labels:
Created at: Thu Apr 17 02:04:39 CEST 2014
State: closed