Equivalent function in HANA DB for json_object - sql

Question

I would like to return the query results into json format in HANA DB.
There is a json_object function in oracle to achieve this requirement, but I am not seeing any function in HANA.
Does anyone knows if this kind of function exists in HANA
For example:
Table Author contains non-json data as follows:
---------------------------------------------
| firstName | lastName |
---------------------------------------------
| Paulo | Coelho |
| George | Orwell |
---------------------------------------------
write a select statement to return result as json.
In Oracle it can be returned using query:
SELECT json_object(
KEY 'firstName' VALUE author.first_name,
KEY 'lastName' VALUE author.last_name
)
FROM author
Output looks like this:
---------------------------------------------
| json_array |
---------------------------------------------
| {"firstName":"Paulo","lastName":"Coelho"} |
| {"firstName":"George","lastName":"Orwell"} |
----------------------------------------------
Does anyone knows query or function in HANA to achieve the same result?

Answer 1

you can use the already mentioned function in SAP HANA too
JSON_QUERY (
<JSON_API_common_syntax>
[ <JSON_output_clause> ]
[ <JSON_query_wrapper_behavior> ]
[ <JSON_query_empty_behavior> ON EMPTY ]
[ <JSON_query_error_behavior> ON ERROR ]
)
research

Answer 2

For 2.0 SP04 and above there's a for json addition to the select statement. As documentation says, it is only permitted in subqueries, so you need to select individual columns in subselect (if you need a result set of JSON objects) of generate a JSON array as a single scalar result. Column names are inherited from subquery aliases.
Case 1:
with a as (
select 'AAA' as field1, 'Value 1' as val from dummy union all
select 'BBB' as field1, 'Value 2' as val from dummy
)
select
/*Use correlated subquery with single row*/
json_value((select a.field1, a.val from dummy for json), '$[0]') as res
from a
Or more effort to type-in, but less structure-dependent:
with a as (
select 'AAA' as field1, 'Value 1' as val from dummy union all
select 'BBB' as field1, 'Value 2' as val from dummy
)
, json_source as (
/*Intermediate query to use as correlation source in JSON_TABLE*/
select (select * from a for json) as tmp_json
from dummy
)
select json_parsed.*
from json_source,
json_table(
json_source.tmp_json
/*Access individual items*/
, '$[*]'
columns (
res nvarchar(1000) format json path '$'
)
) as json_parsed
Both return:
RES
{"FIELD1":"AAA","VAL":"Value 1"}
{"FIELD1":"BBB","VAL":"Value 2"}
Or as a scalar query returning JSON array (Case 2):
with a as (
select 'AAA' as field1, 'Value 1' as val from dummy union all
select 'BBB' as field1, 'Value 2' as val from dummy
)
select *
from (select * from a for json)
JSONRESULT
[{"FIELD1":"AAA","VAL":"Value 1"},{"FIELD1":"BBB","VAL":"Value 2"}]