Hive Query Where Json Like or Equals - sql

Question

I'm new to learning about Hive and Hadoop. There is a table that I've created, which references a certain location containing files.
CREATE DATABASE IF NOT EXISTS <dbname>
LOCATION '/user/<username>/hive/<dbname>.db';
USE <dbname>;
CREATE EXTERNAL TABLE IF NOT EXISTS my_table (json STRING)
PARTITIONED BY (year INT, month INT, day INT)
STORED AS Parquet
LOCATION '/my-data/my/files';
This table has four columns: year, month, day, and json.
The json would look something like:
{
"t_id":"user.login",
"e_time":"2014-11-30T23:59:52Z",
"user_email_address":"someemail#email.com",
"la_id":"10",
"dbnum":16,
"remote_ip":"171.154.1.8",
"server_name":"some.server",
"protocol":"IMAPS",
"secure":true,
"result":"success"
}
A basic query, that works, looks something like this:
SELECT json FROM mydb WHERE year=2015 AND month=12 LIMIT 10;
What I would like to do is have a where clause where I could filter on the json fields listed above. I imagine that it would look like the following, but it does not work:
SELECT get_json_object(mytable.json, '$.t_id') as whatever
FROM mytable
WHERE year=2015 AND month=12 AND json like '%user.login%' LIMIT 1;
Or better yet, be able to query based on the json like so:
SELECT COUNT(*)
FROM mytable
WHERE json.t_id = 'user.login'
AND json.someDate > ... and so on...
Any advice is appreciated.

Answer 1

try this query:
select b.t_id from my_table a lateral view json_tuple(a.json,'t_id') b as t_id where a.year=2015 and a.month=12 LIMIT 10;
you can call another key in the json_tuple and use it in a where clause as well. e.g.:
select b.t_id from my_table a lateral view json_tuple(a.json,'t_id','result') b as t_id, result where a.year=2015 and a.month=12 and b.result ='true' LIMIT 10;

Answer 2

You need to have JSON Serde to read the data in JSON format. You can actually create table using JSON format then query normal table.
-- Add jar file using "add jar /path-to/hive-json-serde-0.2.jar"
CREATE EXTERNAL TABLE states_json (state_short_name string, state_full_name string)
ROW FORMAT SERDE 'org.apache.hadoop.hive.contrib.serde2.JsonSerde'
LOCATION '/user/hduser/states.json';
states.json have data like {"state_short_name":"CA", "state_full_name":"California"}