Hi Danny, Thanks for the suggestion, but that did not solve the problem, still getting the same exception, Not sure If I am missing something ? Do you have an example of this usage ? Again the goal here is to select a Row for a Row as an example this is the column type sketch outerRow(address_kind, address_inner_row(ZipCode, StreetNum,....)) SELECT outerRow.address_inner_row FROM table.
FYI select outerRow.address_kind works because it is a scalar and after adding your suggestion I see that select address_kind from table. On Mon, Jun 15, 2020 at 7:21 PM Danny Chan <[email protected]> wrote: > Hi, when you create a structure type, you should choose > StructKind.PEEK_FIELDS instead, which let you to access the nested fields > with DOT, i.e. “a.b.c”. > > Best, > Danny Chan > 在 2020年6月16日 +0800 AM4:21，Slim Bouguerra <[email protected]>，写道： > > I am using this thread since the question seems related. > > As of now I can not say a way to project a nested record (FYI scalar > > works). https://jira.apache.org/jira/browse/CALCITE-4065 > > @Igor any idea if this can be done without major work on the > > SqlRelToRelConverter ? > > Also I am thinking about turning off the flatten stage but not sure this > is > > going to happen (seems like a pandora box kind of flag where you do not > > know what to expect) > > > > On Thu, Oct 24, 2019 at 3:53 AM Igor Guzenko <[email protected] > > > > wrote: > > > > > Hello Naveen, > > > > > > 1. If I understand correctly, then yes you can extract nested fields > from > > > struct type. The syntax depends on StructKind value for your data type, > > > for example for FULLY_QUALIFIED struct you should first > > > make alias for your table and then request nested field like, > > > table_alias.struct_column.nested_field. In rel tree such expressions > are > > > presented as RexCall with SqlItemOperator operator. > > > 2. Yes, this ability was implemented in CALCITE-3138 [1]. It builds > call to > > > ROW type constructor function on top of flattened tree for necessary > > > columns. > > > 3. Yes, examples of such functions are ROW(...), ANY_VALUE(...) etc. > > > > > > In current implementation of flattener invocation of ROW constructor > > > function is done despite of null handling same issue exists for some > > > aggregate function flattening, like COUNT(struct_column). > > > Proper null handling is real pain for flattener, original idea was to > > > handle special null indicator for each flattened struct, but in > practice I > > > recognized that it's really hard to deal with flattened fields indices > when > > > related methods are called from very different points, so for now the > > > problem remains unsolved. > > > If you can't avoid dealing with null values in your struct columns you > > > could try to avoid invocation to SqlToRelConverter.flattenTypes(...) > and > > > check whether final plan acceptable for you. As far as I know > > > there is no reading material for given topic, you can investigate > source > > > code by debugging RelStructuredTypeFlattener and reading some related > plans > > > in SqlToRelConverterTest.java and SqlToRelConverterTest.xml. > > > > > > [1] https://issues.apache.org/jira/browse/CALCITE-3138 > > > > > > Thanks, > > > Igor > > > > > > On Thu, Oct 24, 2019 at 12:57 PM Naveen Kumar > > > <[email protected]> wrote: > > > > > > > Hi, > > > > > > > > I work at Flipkart, we are using Calcite in our streaming platform. > In > > > most > > > > of our use cases, input data is nested. I understand Calcite flattens > > > > structs in scan and references fields positionally. > > > > > > > > I had a few questions on handling nested data - > > > > > > > > 1. Can RelNode DAG work with nested data (instead of flattened > fields) > > > > by referencing fields through their nested structure eg, > > > > data.order.orderId > > > > 2. In the current flattened behavior, can output of a query be a > > > struct. > > > > Eg if *orderId, orderData.timestamp, orderData.category* are output > of > > > > select query, can I declaratively organise output to below json > > > > structure - > > > > 1. > > > > > > > > > > > > > > > > > > > > > > > > *{ "orderId": "order1", "orderData": { "timestamp": 1571904384814, > > > > "category": "shoes" } }* > > > > 3. Can output of a UDF be struct type > > > > > > > > Please point me to any reading material or example that would help > with > > > > these questions. > > > > > > > > Regards, > > > > Naveen > > > > > > > > -- > > > > > > > > > > > > > > > > > > > > > > > > *-----------------------------------------------------------------------------------------* > > > > > > > > > > > > *This email and any files transmitted with it are confidential and > > > > intended solely for the use of the individual or entity to whom they > are > > > > addressed. If you have received this email in error, please notify > the > > > > system manager. This message contains confidential information and is > > > > intended only for the individual named. If you are not the named > > > > addressee, > > > > you should not disseminate, distribute or copy this email. Please > notify > > > > the sender immediately by email if you have received this email by > > > mistake > > > > and delete this email from your system. If you are not the intended > > > > recipient, you are notified that disclosing, copying, distributing or > > > > taking any action in reliance on the contents of this information is > > > > strictly prohibited.***** > > > > > > > > **** > > > > > > > > *Any views or opinions presented in this > > > > email are solely those of the author and do not necessarily represent > > > > those > > > > of the organization. Any information on shares, debentures or similar > > > > instruments, recommended product pricing, valuations and the like > are for > > > > information purposes only. It is not meant to be an instruction or > > > > recommendation, as the case may be, to buy or to sell securities, > > > > products, > > > > services nor an offer to buy or sell securities, products or services > > > > unless specifically stated to be so on behalf of the Flipkart group. > > > > Employees of the Flipkart group of companies are expressly required > not > > > to > > > > make defamatory statements and not to infringe or authorise any > > > > infringement of copyright or any other legal right by email > > > > communications. > > > > Any such communication is contrary to organizational policy and > outside > > > > the > > > > scope of the employment of the individual concerned. The organization > > > will > > > > not accept any liability in respect of such communication, and the > > > > employee > > > > responsible will be personally liable for any damages or other > liability > > > > arising.***** > > > > > > > > **** > > > > > > > > *Our organization accepts no liability for the > > > > content of this email, or for the consequences of any actions taken > on > > > the > > > > basis of the information *provided,* unless that information is > > > > subsequently confirmed in writing. If you are not the intended > recipient, > > > > you are notified that disclosing, copying, distributing or taking any > > > > action in reliance on the contents of this information is strictly > > > > prohibited.* > > > > > > > > > > > > > > > > > > > > _-----------------------------------------------------------------------------------------_ > > > > > > > > > > > >
