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https://issues.apache.org/jira/browse/TAJO-939?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14060548#comment-14060548
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ASF GitHub Bot commented on TAJO-939:
-------------------------------------
Github user jihoonson commented on a diff in the pull request:
https://github.com/apache/tajo/pull/71#discussion_r14873254
--- Diff:
tajo-core/src/main/java/org/apache/tajo/engine/planner/LogicalPlanPreprocessor.java
---
@@ -197,6 +199,17 @@ public LogicalNode visitProjection(PreprocessContext
ctx, Stack<Expr> stack, Pro
}
NamedExpr[] projectTargetExprs = expr.getNamedExprs();
+ NameRefInSelectListNormalizer normalizer = new
NameRefInSelectListNormalizer();
+
+ for (int i = 0; i < expr.getNamedExprs().length; i++) {
+ NamedExpr namedExpr = expr.getNamedExprs()[i];
--- End diff --
It would be better use the above 'projectTargetExprs' variable.
> Refactoring the column resolver in LogicalPlan
> ----------------------------------------------
>
> Key: TAJO-939
> URL: https://issues.apache.org/jira/browse/TAJO-939
> Project: Tajo
> Issue Type: Bug
> Components: planner/optimizer
> Reporter: Hyunsik Choi
> Assignee: Hyunsik Choi
> Fix For: 0.9.0
>
>
> The main role of the column resolver is to find the exact column in a
> relation or a temporal column to which a variable name points. We have used a
> monolithic column resolver to deal with lots of cases.
> But, resolving a name should play different roles according to at which the
> name is placed.
> For example, 1) a column name in select list always points one of fields in
> relations, 2) a column name in WHERE clause can point to one of fields in
> relations or one of aliased temporal fields in select list. If there are
> duplicated, the column name firstly chooses the field in relations. 3) a
> column name in ORDER BY clause is similar to that in WHERE clause, but it
> firstly chooses one of aliased temporal fields in select list.
> The current column resolver does not consider the above rules. As a result,
> it works incorrectly in some cases where a sql statement includes the same
> name references, actually indicating one field in relation and one aliased
> temporal field in select list. We should fix it.
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