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https://issues.apache.org/jira/browse/CALCITE-545?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Julian Hyde updated CALCITE-545:
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Description:
When we have deduced that an expression can only have one value, replace the
expression with that value. This is beneficial because it will allow us to do
more column trimming.
Example 1
{code}select deptno from emp where deptno = 10{code}
can become
{code}select 10 from emp where deptno = 10{code}
Example 2 (using inference, as in CALCITE-360)
{code}select emp.deptno
from emp join dept using (deptno)
where dept.deptno = 10{code}
can become
{code}select 10
from emp join dept using (deptno)
where dept.deptno = 10{code}
was:
When we have deduced that an expression can only have one value, replace the
expression with that value. This is beneficial because it will allow us to do
more column trimming.
Example 1
{{select deptno from emp where deptno = 10}}
can become
{{select 10 from emp where deptno = 10}}
Example 2 (using inference, as in CALCITE-360)
{{select emp.deptno
from emp join dept using (deptno)
where dept.deptno = 10}}
can become
{{select 10
from emp join dept using (deptno)
where dept.deptno = 10}}
> When a projected expression can only have one value, replace with that
> constant
> -------------------------------------------------------------------------------
>
> Key: CALCITE-545
> URL: https://issues.apache.org/jira/browse/CALCITE-545
> Project: Calcite
> Issue Type: Bug
> Reporter: Julian Hyde
> Assignee: Julian Hyde
>
> When we have deduced that an expression can only have one value, replace the
> expression with that value. This is beneficial because it will allow us to do
> more column trimming.
> Example 1
> {code}select deptno from emp where deptno = 10{code}
> can become
> {code}select 10 from emp where deptno = 10{code}
> Example 2 (using inference, as in CALCITE-360)
> {code}select emp.deptno
> from emp join dept using (deptno)
> where dept.deptno = 10{code}
> can become
> {code}select 10
> from emp join dept using (deptno)
> where dept.deptno = 10{code}
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