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https://issues.apache.org/jira/browse/CALCITE-3077?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16843146#comment-16843146
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Stamatis Zampetakis commented on CALCITE-3077:
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I think you are on the right track SparkSqlDialect seems to be the right place.
You may also need to touch RelToSqlConverter. Another place that might be
relevant to look at is RexSqlConvertletTable.
> Rewrite CUBE&ROLLUP&CUBE queries in SparkSqlDialect
> ---------------------------------------------------
>
> Key: CALCITE-3077
> URL: https://issues.apache.org/jira/browse/CALCITE-3077
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.20.0
> Reporter: Feng Zhu
> Priority: Major
>
> *Background:* we are building a platform that adopts Calcite to process
> (i.e., parse&validate&convert&optimize) SQL queries and then regenerate the
> final SQL. For the purpose of handling large volume data, we use the popular
> SparkSQL engine to execute the generated SQL query.
> However, we found a great part of real-world test cases failed, due to syntax
> differences of
> *_CUBE/ROLLUP/GROUPING SETS_* clauses. Spark SQL dialect supports only "WITH
> ROLLUP&CUBE" in the "GROUP BY" clause. The corresponding grammer [1] is
> defined as below.
> {code:java}
> aggregation
> : GROUP BY groupingExpressions+=expression (','
> groupingExpressions+=expression)* (
> WITH kind=ROLLUP
> | WITH kind=CUBE
> | kind=GROUPING SETS '(' groupingSet (',' groupingSet)* ')')?
> | GROUP BY kind=GROUPING SETS '(' groupingSet (',' groupingSet)* ')'
> ;
> {code}
> To fill this gap, I think we need to rewrite CUBE/ROLLUP/GROUPING SETS
> clauses in SparkSqlDialect, especially for some complex cases.
> {code:java}
> group by cube ((a, b), (c, d))
> group by cube(a,b), cube(c,d)
> {code}
> [1]https://github.com/apache/spark/blob/master/sql/catalyst/src/main/antlr4/org/apache/spark/sql/catalyst/parser/SqlBase.g4
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