BigQuery - Add elements from array into array of structs - sql

Question

I have a struct which looks like this:
{"event": {
"timestamp": [
"2019-01-13 17:21:08.570140 UTC",
"2019-01-14 14:10:55.475515 UTC",
"2019-01-09 14:02:51.848917 UTC"
],
"properties": [
{"device_model": "iPhone", "country": "United Kingdom"},
{"device_model": "Android", "country": "United States"},
{"device_model": "iPhone", "country": "Sweden"}
]
}
I would like to achieve this: so that each timestamp enters corresponding struct.
{"event": [
{"timestamp": "2019-01-13 17:21:08.570140 UTC","device_model":
"iPhone", "country": "United Kingdom"},
{"timestamp": "2019-01-14 14:10:55.475515 UTC", "device_model":
"Android", "country": "United States"},
{"timestamp": "2019-01-09 14:02:51.848917 UTC", "device_model":
"iPhone", "country": "Sweden"}
]
}
I created the current structure from a query like this:
WITH
events AS (
SELECT
"customer_1" AS customer_id,
"timestamp_1" AS timestamp,
STRUCT("iphone" AS device_model,
"uk" AS country ) AS properties
UNION ALL
SELECT
"customer_2" AS customer_id,
"timestamp_2" AS timestamp,
STRUCT("android" AS device_model,
"us" AS country) AS properties
UNION ALL
SELECT
"customer_2" AS customer_id,
"timestamp_3" AS timestamp,
STRUCT("iphone" AS device_model,
"sweden" AS country) AS properties )
SELECT
customer_id,
STRUCT(ARRAY_AGG(timestamp) AS timestamp,
ARRAY_AGG(properties) AS properties) AS event
FROM
events
GROUP BY
customer_id
How can I modify the query to achieve the desired structure?
--- Edit
I could do it this way, but this requires knowing the schema of properties at the time when I am generating query - which is possible, but not very pretty. Is there a simpler way?
WITH
events AS (
SELECT
"customer_1" AS customer_id,
"timestamp_1" AS timestamp,
STRUCT("iphone" AS device_model,
"uk" AS country ) AS properties
UNION ALL
SELECT
"customer_2" AS customer_id,
"timestamp_2" AS timestamp,
STRUCT("android" AS device_model,
"us" AS country) AS properties
UNION ALL
SELECT
"customer_2" AS customer_id,
"timestamp_3" AS timestamp,
STRUCT("iphone" AS device_model,
"sweden" AS country) AS properties )
SELECT
customer_id,
ARRAY_AGG(properties) AS event
FROM (
SELECT
customer_id,
struct(timestamp as timestamp,
properties.device_model as device_model,
properties.country as country) as properties
FROM
events)
GROUP BY
customer_id

Answer 1

You could do something like this leveraging SELECT AS STRUCT and using properties as a selector.
SELECT
customer_id,
ARRAY_AGG(properties) AS prop
FROM (
SELECT
customer_id,
(
SELECT
AS STRUCT timestamp,
properties.*) AS properties
FROM
events e )
GROUP BY
1
this returns:
[
{
"customer_id": "customer_1",
"prop": [
{
"timestamp": "timestamp_1",
"device_model": "iphone",
"country": "uk"
}
]
},
{
"customer_id": "customer_2",
"prop": [
{
"timestamp": "timestamp_2",
"device_model": "android",
"country": "us"
},
{
"timestamp": "timestamp_3",
"device_model": "iphone",
"country": "sweden"
}
]
}
]
You could further write the piece like:
SELECT AS STRUCT e.* except(customer_id)