Vineet Garg created CALCITE-1851:
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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}
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