Support JSONEachRow as response format

[gingerwizard]

Useful for debugging and some use cases e.g. grafana/clickhouse-datasource#148
All responses would be marshalled into a map or struct.

[vladimir-golovchenko]

As an alternative consider returning string:

SELECT toString(tuple(*)) as result
FROM system.functions
LIMIT 3

/*
┌─result───────────────────────────┐
│ ('aes_encrypt_mysql',0,0,'')     │
│ ('decrypt',0,0,'')               │
│ ('wordShingleMinHashArg',0,0,'') │
└──────────────────────────────────┘
*/

[benwen-instacart]

Need the same support. For example query

select * from table_name FORMAT JSONEachRow

where the table has id and version columns.
and the expected result is like

{"id":1, "version":1}
{"id":2, "version":2}

The ClickHouse client returns the expected result. Expect the driver can return the same.

[jkaflik]

Currently, driver support NATIVE format only. We plan to introduce in/out multiple formats support in v3.

[benwen-instacart]

Thanks @jkaflik ! Just curious what is the timeline for v3?

[jkaflik]

@benwen-instacart unfortunetely, we don't have it yet defined.