[GitHub] [druid] chenyuzhi459 opened a new pull request #11017: Fix subquery with order by

[GitBox <gi...@apache.org>]

chenyuzhi459 opened a new pull request #11017:
URL: https://github.com/apache/druid/pull/11017


   Fixes #9871
   
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   ### Description
   
   Problem:
   In the jdbc connection, it is invalid to use subquery with `order by`  clause . It will throw excepiton with msg: `Table 'xxx' not found`
   
   Reason:
   The exception was thrown in `DruidPlanner.prepare()`, let 's see  the orginal code:
   ```
     public PrepareResult prepare(final String sql) throws SqlParseException, ValidationException, RelConversionException
     {
       reset();
       SqlNode parsed = planner.parse(sql);
       SqlExplain explain = null;
       if (parsed.getKind() == SqlKind.EXPLAIN) {
         explain = (SqlExplain) parsed;
         parsed = explain.getExplicandum();
       }
       final SqlNode validated = planner.validate(parsed);
       RelRoot root = planner.rel(validated);
       RelDataType rowType = root.validatedRowType;
   
       SqlValidator validator = getValidator();
       RelDataType parameterTypes = validator.getParameterRowType(validator.validate(parsed));
   
       if (explain != null) {
         final RelDataTypeFactory typeFactory = root.rel.getCluster().getTypeFactory();
         return new PrepareResult(getExplainStructType(typeFactory), parameterTypes);
       }
       return new PrepareResult(rowType, parameterTypes);
     }
   ```
   The problem should focus on `validator.validate(parsed)`, we try to validate `parsed` sqlnode to get parameterTypes, However, when we use order by clause, the `order by` item will be pushed down into `sqlSelect` node through the method invoke chain
   ``
   
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[GitHub] [druid] clintropolis merged pull request #11017: Fix subquery with order by

[GitBox <gi...@apache.org>]

clintropolis merged pull request #11017:
URL: https://github.com/apache/druid/pull/11017


   


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