See inline 2016-01-25 19:16 GMT+03:00 Pavel Tupitsyn <ptupit...@gridgain.com>:
> Thank you Sergi, more questions: > > - How do I get the result of an aggregate? Via Fields query? Will it always > be a single value, or a value per node? > Yes, using fields query. Supported aggregates must work correctly across cluster. > - If field names are flattened, what are QueryEntity.aliases for? Javadoc > talks about dot notation, I thought it is for nested fields. > Exactly aliases are needed to resolve duplication cases. For example you have entity Person it has field `child` which has field `age` and field `car` which has field `age` as well. You can specify in config that "child.age" must have SQL alias "child_age" and "car.age" will have alias "car_age". Obviously you can't use `car.age` notation in sql as is. > - What is the purpose of SqlQuery.type? We use simple name of the class for > it everywhere. Does it relate to type id mapping somehow? > Sometimes (when we work with binary objects) we don't have classes at all. > - I tried to use _key/_val aliases and could not get them to work: > * "_val.Age > ?": Failed to parse query: SELECT > "cache".QueryPerson._key, "cache".QueryPerson._val FROM "cache".QueryPerson > WHERE _val.Age > ? > There are no dot notation in SQL. You can operate on _val but not on _val.property1.property2.property25. > * "_key > ?": Caused by: org.h2.jdbc.JdbcSQLException: Deserialization > failed, cause: "class org.apache.ignite.binary.BinaryObjectException: Not > enough data to read the value [position=1, requiredBytes=4, > remainingBytes=0]"; SQL statement: SELECT "cache".QUERYPERSON._KEY __C0, > "cache".QUERYPERSON._VAL __C1 FROM "cache".QUERYPERSON WHERE _KEY > ?1 > [90027-175] > Looks like a bug to me. Could you open Jira issue with simple reproducible test? Sergi > > > > On Mon, Jan 25, 2016 at 6:38 PM, Sergi Vladykin <sergi.vlady...@gmail.com> > wrote: > > > - Yes, in SQL it is possible to query cache key and value using aliases > > _key and _val respectively. > > - Aggregate functions like SUM, AVG, MIN, MAX are supported. > > - Nested fields are supported and they are flattened, so name collisions > > are prohibited. > > > > Sergi > > > > 2016-01-25 15:26 GMT+03:00 Pavel Tupitsyn <ptupit...@gridgain.com>: > > > > > Igniters, > > > > > > In relation to .NET LINQ task [1], I'd like to know as much as possible > > > about Ignite-specific SQL syntax. Our docs [2] do not cover everything. > > > > > > * Is it possible to query cache keys? E.g. "key > 10", or "key.field = > > 1"? > > > * Is it possible to query scalars, like "sum()"? > > > * What about nested fields? From examples, I see that nested fields get > > > flattened, so instead of Address.Zip you can just use Zip. Are there > any > > > limitations? What if there is field name collision? > > > > > > Where should I look to understand this better? > > > > > > Thanks. > > > > > > [1] https://issues.apache.org/jira/browse/IGNITE-1630 > > > [2] https://apacheignite.readme.io/docs/sql-queries > > > > > > -- > > > -- > > > Pavel Tupitsyn > > > GridGain Systems, Inc. > > > www.gridgain.com > > > > > > > > > -- > -- > Pavel Tupitsyn > GridGain Systems, Inc. > www.gridgain.com >
