Loading contents of json array in redshift - amazon-redshift

Question

I'm setting up redshift and importing data from mongo. I have succeeded in using a json path file for a simple document but am now needing to import from a document containing an array.
{
"id":123,
"things":[
{
"foo":321,
"bar":654
},
{
"foo":987,
"bar":567
}
]
}
How do I load the above in to a table like so:
select * from things;
id | foo | bar
--------+------+-------
123 | 321 | 654
123 | 987 | 567
or is there some other way?
I can't just store the json array in a varchar(max) column as the content of Things can exceed 64K.

Answer 1

Given
db.baz.insert({
"myid":123,
"things":[
{
"foo":321,
"bar":654
},
{
"foo":987,
"bar":567
}
]
});
The following will display the fields you want
db.baz.find({},{"things.foo":1,"things.bar":1} )
To flatten the result set use aggregation like so
db.baz.aggregate(
{"$group": {"_id": "$myid", "things": { "$push" : {"foo":"$things.foo","bar":"$things.bar"}}}},
{
$project : {
_id:1,
foo : "$things.foo",
bar : "$things.bar"
}
},
{ "$unwind" : "$foo" },
{ "$unwind" : "$bar" }
);