[jira] [Created] (CALCITE-545) When a projected expression can only have one value, replace with that constant

["Julian Hyde (JIRA)" <ji...@apache.org>]

Julian Hyde created CALCITE-545:
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             Summary: 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

{{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}}




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