You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@calcite.apache.org by "Vineet Garg (JIRA)" <ji...@apache.org> on 2017/06/20 00:50:00 UTC
[jira] [Created] (CALCITE-1851) Decorrelation should get rid of
correlated predicates while decorrelation filter condition
Vineet Garg created CALCITE-1851:
------------------------------------
Summary: Decorrelation should get rid of correlated predicates while decorrelation filter condition
Key: CALCITE-1851
URL: https://issues.apache.org/jira/browse/CALCITE-1851
Project: Calcite
Issue Type: Improvement
Components: core
Reporter: Vineet Garg
Assignee: Julian Hyde
For queries such as
{code:sql}
select sal from emp
where empno IN (
select deptno from dept
where emp.job = dept.name)
{code}
Filter condition for correlated predicate e.g. {{=($cor0.JOB, $1)}} is transformed into equality predicate on same column e.g. {{$1=$1}} after calling {{decorrelateExpr}} (if value generator is not generated). This is further simplified into {{$1 is not null}}.
We do not need to generate and simplify such predicate expression, instead it could be completely removed. This will help support cases other than equality correlated predicates for which value generated is not required. e.g.
{code:sql}
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)