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https://issues.apache.org/jira/browse/CALCITE-1208?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15289511#comment-15289511
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Maryann Xue commented on CALCITE-1208:
--------------------------------------
Hi [~jni], please check this file for a (hopefully complete) list of query
examples
https://github.com/apache/calcite/compare/master...maryannxue:calcite-1208#diff-0a6b96592dd053cb0697ea9ebfa3eea4.
Let me know if it helps. Phoenix follows the hierarchical column naming
convention of HBase, which is ColumnFamilyName.ColumnName, but this is only for
name resolving. We would like to have the a flat structure as table type.
> Improve two-level column structure handling
> -------------------------------------------
>
> Key: CALCITE-1208
> URL: https://issues.apache.org/jira/browse/CALCITE-1208
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.7.0
> Reporter: Maryann Xue
> Assignee: Maryann Xue
>
> Calcite now has support for nested column structure in parsing and
> validation, by representing the inner-level columns as a RexFieldAccess based
> on a RexInputRef. Meanwhile it does not flatten the inner level structure in
> wildcard expansion, which would then cause an UnsupportedOperationException
> in Avatica.
>
> The idea is to take into account this nested structure in column resolving,
> but to flatten the structure when translating to RelNode/RexNode.
> For example, if the table structure is defined as
> {code}VARCHAR K0,
> VARCHAR C1,
> RecordType(INTEGER C0, INTEGER C1) F0,
> RecordType(INTEGER C0, INTEGER C2) F1{code}
> , it should be viewed as a flat type like
> {code}VARCHAR K0,
> VARCHAR C1,
> INTEGER F0.C0,
> INTEGER F0.C1,
> INTEGER F1.C0,
> INTEGER F1.C2{code}
> , so that:
> 1) Column reference "K0" is translated as {{$0}}
> 2) Column reference "F0.C1" is translated as {{$3}}
> 3) Wildcard "*" is translated as: {{$0, $1, $2, $3, $4, $5}}
> 4) Complex-column wildcard "F1.*", which is translated as {{$2, $3}}
> And we would like to resolve columns based on the following rules (here we
> only consider the "suffix" part of the qualified names, which means the table
> resolving is already done by this time):
> a) A two-part column name is matched with its first-level column name and its
> second-level column name. For example, "F1.C0" corresponds to $4; "F1,X" will
> throw a column not found error.
> b) A single-part column name is matched against non-nested columns first, and
> if no matches, it is then matched against those second-level column names.
> For example, "C1" will be matched as "$1" instead of "$3", since non-nested
> columns have a higher priority; "C2" will be matched as "$5"; "C0" will lead
> to an ambiguous column error, since it exists under both "F0" and "F1".
> c) We would also like to have a way for defining "default first-level column"
> so that it has a precedence in column resolving over other first-level
> columns. For example, if "F0" is defined as default, "C0" will not cause an
> ambiguous column error, but instead be matched as "$2".
> d) Reference to first-level column only without wildcard is not allowed,
> e.g., "F1".
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