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https://issues.apache.org/jira/browse/CALCITE-4463?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17263843#comment-17263843
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yanjing.wang edited comment on CALCITE-4463 at 1/13/21, 2:43 AM:
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Hi, [~julianhyde], [~amaliujia] ; I have submitted a
[pr|https://github.com/apache/calcite/pull/2324] to solve this problem and a
test to verify, much appreciations for your suggestions.
was (Author: yanjing.wang):
Hi, [~julianhyde], [~amaliujia] ; I have submitted a pr to solve this problem
and a test to verify, much appreciations for your suggestions.
> dialect.unparseOffsetFetch method doesn't apply to "SqlOrderBy" sql node
> ------------------------------------------------------------------------
>
> Key: CALCITE-4463
> URL: https://issues.apache.org/jira/browse/CALCITE-4463
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.26.0
> Environment: jvm: open-jdk8
>
> calcite: 1.26.0
> Reporter: yanjing.wang
> Priority: Major
> Attachments: image-2021-01-12-10-06-29-813.png
>
>
> in SqlOrderBy$Operator class, the unparse method code "offset and fetch"
> hardly and close the door to transform my sql to "limit x offset y style".
>
> !image-2021-01-12-10-06-29-813.png!
>
> my unparse sql code:
> {code:java}
> String sql = "select concat(a.id,'-',b.id) , a.name from xxx.bb limit 5";
> SqlDialect SPARK = new
> SparkSqlDialect(SqlDialect.EMPTY_CONTEXT
> .withDatabaseProduct(SqlDialect.DatabaseProduct.SPARK)
> .withIdentifierQuoteString("`").withNullCollation(NullCollation.LOW)
> .withLiteralQuoteString("'").withLiteralEscapedQuoteString("''")
>
> .withUnquotedCasing(Casing.UNCHANGED).withQuotedCasing(Casing.UNCHANGED));
> SqlParser.Config configBuilder =
> SqlParser.config()
> .withParserFactory(SqlBabelParserImpl.FACTORY)
> .withConformance(SqlConformanceEnum.LENIENT);
> SqlParser sqlParser = SqlParser.create(sql, configBuilder);
> try {
> SqlNode sqlNode = sqlParser.parseQuery();
> SqlString sqlString = sqlNode.toSqlString(SPARK);
> System.out.println(sqlString);
> } catch (SqlParseException e) {
> e.printStackTrace();
> }{code}
> result:
> {code:java}
> SELECT `CONCAT`(`A`.`ID`, '-', `B`.`ID`), `A`.`NAME` FROM `XXX`.`BB` FETCH
> NEXT 5 ROWS ONLY
> {code}
> the "limit 5" clause shouldn't be transformed to "FETCH NEXT 5000 ROWS ONLY".
>
> i dive into "parser.jj" file and find the following lines in "SqlSelect()"
> production.
> {code:java}
> { return new SqlSelect(s.end(this), keywordList, new SqlNodeList(selectList,
> Span.of(selectList).pos()), fromClause, where, groupBy, having, windowDecls,
> null, null, null, new SqlNodeList(hints, getPos())); }
> {code}
>
> the "SqlSelect" sql node always receive null orderby, offset and fetch. so
> the "limit" clause will always be processed in "SqlOrderBy" sql node, and
> the "unparse offset and fetch" can't be processed within specific sql dialect.
>
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