Hi there,
I want to create a new JSON Field/Column type. I know there exists
get_json_object(), but the things is I want to multiple JSON
operations in a single select statement and don't want to incur the
cost of parsing the JSON over and over again, because our json
structures are quite large.
Our schema is two fields - the first is a string of some sort used as
an id, and the second is a huge JSON structure. I want to be able
write sql like the following:
select Foo(json), Bar(json), Baz(json) where Quux(json) like '%hello%';
Foo(), Bar(), Baz() and Quux() are all UDF's that operate on json.
Right now what I'm doing is storing the JSON as a string and in each
of those UDF's I am de-serializing the json, and returning another
string.
Ideally I'd want to be able to return JSON objects from these UDF's so
I could compose my functions like "Foo(Bar(Baz(json))"
I'm thinking I need to create a SerDe but SerDe's seem to work at the
table level, not at the field level (in other words, I just need a
custom field, not a entire custom table type...or do I!?)
Also, if there's any docs on writing custom SerDe's please let me
know...I haven't been able to find much.
Thanks!
Bobby
