Thanks Yong!
On Mon, Apr 7, 2014 at 5:07 PM, java8964 <java8...@hotmail.com> wrote: > Hi, Narayanan: > > The current problem is that for a generic solution, there is no way that we > know that element in the Json is an array. Keep in mind that in any element > of Json, it could be any valid structure. So it could be array, another > structure, or map etc. > > You know your data, so you can say in this level, it is array. But computer > doesn't know, that is why you need to provide a schema. > > Think about it, in programming, we can cast that to array, but normally that > is NOT a good solution, so for a generic solution like any hadoop json UDF, > it will and should ask for a schema. > > For you case, if you know the data, it gets to be array, then write your own > UDF to cast it to an array, without any schema. But I don't think any good, > generic Json UDFs will support that for your case. > > Yong > >> Date: Mon, 7 Apr 2014 16:47:44 -0700 >> Subject: Re: get_json_object for nested field returning a String instead >> of an Array >> From: knarayana...@gmail.com >> To: user@hive.apache.org > >> >> Thanks Peyman. >> >> Actually the problem with Hive-Json-Serde is that we need to provide >> the entire schema upfront while creating the table. >> >> My requirement is that we just project/aggregate on the fields using >> get_json_object after creating the external table without schema. This >> way the external table is agnostic to any new schema changes. >> >> Would love to get a solution for converting get_json_object to return >> an Array instead of a string.. Can we use any Hive UDFs to convert >> string into an explodable Array object ? >> >> Thanks >> Narayanan >> >> On Mon, Apr 7, 2014 at 4:14 PM, Peyman Mohajerian <mohaj...@gmail.com> >> wrote: >> > perhaps: https://github.com/rcongiu/Hive-JSON-Serde >> > >> > >> > On Mon, Apr 7, 2014 at 6:52 PM, Narayanan K <knarayana...@gmail.com> >> > wrote: >> >> >> >> Hi all >> >> >> >> I am using get_json_object to read a json text file. I have created >> >> the external table as below : >> >> >> >> CREATE EXTERNAL TABLE EXT_TABLE ( json string) >> >> PARTITIONED BY (dt string) >> >> LOCATION '/users/abc/'; >> >> >> >> >> >> The json data has some fields that are not simple fields but fields >> >> which are nested fields like - "field" : [{"id":1},{"id":2}.. ]. >> >> >> >> While using the get_json_object to retrieve that field, it is >> >> returning back a string instead of an Array. Hence I am not able to >> >> explode the array as it is a string. >> >> >> >> Is there some way we can get an array of get_json_object instead of a >> >> string so that we can perform explode on this nested field ? or Anyway >> >> we can convert the string into an array so that I can use explode ? >> >> >> >> Thanks in advance, >> >> Narayanan >> > >> >
