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https://issues.apache.org/jira/browse/CALCITE-3138?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16906379#comment-16906379
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Julian Hyde commented on CALCITE-3138:
--------------------------------------
Can you please improve the description? As it stands, it is an untrue
statement.
> Restructuring ROW type fields is not supported
> ----------------------------------------------
>
> Key: CALCITE-3138
> URL: https://issues.apache.org/jira/browse/CALCITE-3138
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: Haisheng Yuan
> Assignee: Igor Guzenko
> Priority: Major
> Labels: pull-request-available
> Attachments: ROW_repro.patch
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> ROW type is not supported to restructure fields after flattening (see
> RelStructuredTypeFlattener.restructureFields), which may cause wrong result.
> Attached patch file can be used to reproduce the issue.
> UPDATE: Some tests require changes in expected results.
> ----------------------------------------------------------------------------------
> TEST CASE: SqlToRelConverterTest.testNestedColumnType()
> ORIGIN RESULTS:
> select empa.home_address.zip from sales.emp_address empa where
> empa.home_address.city = 'abc'
> {code}
> LogicalProject(ZIP=[$4])
> LogicalFilter(condition=[=($3, 'abc':VARCHAR(20))])
> LogicalProject(EMPNO=[$0], STREET=[$1.STREET], CITY=[$1.CITY],
> ZIP=[$1.ZIP], STATE=[$1.STATE], STREET5=[$2.STREET], CITY6=[$2.CITY],
> ZIP7=[$2.ZIP], STATE8=[$2.STATE])
> LogicalTableScan(table=[[CATALOG, SALES, EMP_ADDRESS]])
> {code}
> COMMENT:
> 1. Above in logical filter, condition references to field $3 which is
> ZIP=[$1.ZIP] field from previous project,
> however in original query filtering should be done by CITY field.
> 2. Also the top level project references to $4 field, which is
> STATE=[$1.STATE] field from project, but original
> query requested ZIP field.
>
> Updated expected result shows that both problems are fixed now.
> UPDATED RESULT:
> {code}
> LogicalProject(ZIP=[$3])
> LogicalFilter(condition=[=($2, 'abc')])
> LogicalProject(EMPNO=[$0], STREET=[$1.STREET], CITY=[$1.CITY],
> ZIP=[$1.ZIP], STATE=[$1.STATE], STREET5=[$2.STREET], CITY6=[$2.CITY],
> ZIP7=[$2.ZIP], STATE8=[$2.STATE])
> LogicalTableScan(table=[[CATALOG, SALES, EMP_ADDRESS]])
> {code}
> ----------------------------------------------------------------------------------
> TEST CASE: SqlToRelConverterTest.testStructTypeAlias()
> ORIGIN RESULTS:
> select t.r AS myRow from (select row(row(1)) r from dept) t
> {code}
> LogicalProject(MYROW$$0$$0=[1])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> {code}
> COMMENT:
> 1. Inside the subselect of row(row(1)) type of returned column is
> RecordType(RecordType(INTEGER EXPR$0) EXPR$0),
> but the top level project uses flattened expression and returns to user
> literal 1 with type RecordType(INTEGER MYROW$$0$$0),
> although the type doesn't match type returned by row(row(1)) expression.
> 2. Also it's suspicious that caller expects returned column to have name
> 'myRow' but gets 'MYROW$$0$$0'.
> Updated result collects back flattened expression using row constructor.
>
> UPDATED RESULT:
> {code}
> LogicalProject(MYROW=[ROW(ROW($0))])
> LogicalProject(MYROW$$0$$0=[1])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
> {code}
> ----------------------------------------------------------------------------------
> TEST CASE: SqlToRelConverterTest.testFlattenRecords()
> ORIGIN RESULTS:
> select employees[1] from dept_nested
> {code}
> LogicalProject(EXPR$0=[$0])
> LogicalProject(EXPR$0$0=[ITEM($3, 1).EMPNO], EXPR$0$1=[ITEM($3, 1).ENAME],
> EXPR$0$2=[ITEM($3, 1).DETAIL])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT_NESTED]])
> {code}
> COMMENT:
> 1. Given selection of element by index from array, which by definition
> contain elements of type:
> {code}
> STRUCT<EMPNO:INT,
> ENAME:VARCHAR(10),
> DETAIL:STRUCT<SKILLS:ARRAY<STRUCT<TYPE:VARCHAR(10),
> DESC:VARCHAR(20),
>
> OTHERS:STRUCT<A:VARCHAR(10),B:VARCHAR(10)>>>>>
> {code}
> First problem is that the intermediate project on top of the scan expected to
> return only flattened types.
> But last projection expression returns `DETAIL` field of array element which
> has type STRUCT and contain array
> field named 'SKILLS'.
> 2. The top level project returns incorrect flattened EMPNO:INT field from
> retrieved array element instead
> of whole array element of type struct.
>
> UPDATED RESULT:
> ELEMENT_TYPE = RecordType(INTEGER EMPNO, VARCHAR(10) ENAME,
> RecordType(RecordType(VARCHAR(10) NOT NULL TYPE, VARCHAR(20) NOT NULL DESC,
> RecordType(VARCHAR(10) NOT NULL A, VARCHAR(10) NOT NULL B) NOT
> NULL OTHERS) NOT NULL ARRAY SKILLS) DETAIL)
> SKILL_TYPE = RecordType(RecordType(VARCHAR(10) NOT NULL TYPE, VARCHAR(20) NOT
> NULL DESC, RecordType(VARCHAR(10) NOT NULL A, VARCHAR(10) NOT NULL B) NOT
> NULL OTHERS) NOT NULL ARRAY SKILLS)
> {code}
> LogicalProject(EXPR$0=[CASE($0, null:ELEMENT_TYPE, ROW($1, $2, CASE($3,
> null:SKILL_TYPE, ROW($4))))])
> LogicalProject(IS_NULL_ITEM$6_1=[AS(IS NULL(ITEM($3, 1)),
> 'IS_NULL_ITEM$6_1')], EXPR$0$0=[ITEM($3, 1).EMPNO], EXPR$0$1=[ITEM($3,
> 1).ENAME], IS_NULL_ITEM$6_1DETAIL=[AS(IS NULL(ITEM($3, 1).DETAIL),
> 'IS_NULL_ITEM$6_1DETAIL')], EXPR$0$2$0=[ITEM($3, 1).DETAIL.SKILLS])
> LogicalTableScan(table=[[CATALOG, SALES, DEPT_NESTED]])
> {code}
>
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