BigQuery: Convert record of repeated in repeated record - google-bigquery

Question

I have a BigQuery table represented by this JSON (Record of Repeated)
{
"createdBy": [
"foo",
"foo"
],
"fileName": [
"bar1",
"bar2"
]
}
that I need to convert to Repeated Record
[
{
"createdBy": "foo",
"fileName": "bar1"
},
{
"createdBy": "foo",
"fileName": "bar2"
}
]
To make this conversion you use the index 0 for every array and you created the first object, use the 1 index for the second object, ...
I performed this kind of transformation using a UDF, but the problem is due to BigQuery limits I'm unable to save a VIEW that performs this transformation:
No support for CREATE TEMPORARY FUNCTION statements inside views
Following the full statement to generate a sample table and the function
CREATE TEMP FUNCTION filesObjectArrayToArrayObject(filesJson STRING)
RETURNS ARRAY<STRUCT<createdBy STRING, fileName STRING>>
LANGUAGE js AS """
function filesObjectArrayToArrayObject_execute(files) {
var createdBy = files["createdBy"];
var fileName = files["fileName"];
var output = [];
for(var i=0 ; i<createdBy.length ; i++) {
output.push({ "createdBy" : createdBy[i], "fileName" : fileName[i] });
}
return output;
}
return filesObjectArrayToArrayObject_execute(JSON.parse(filesJson));
""";
WITH sample_table AS (
SELECT STRUCT<createdBy ARRAY<STRING>, fileName ARRAY<STRING>>(
["foo", "foo"],
["bar1", "bar2"]
) AS files
)
SELECT
files AS filesOriginal,
filesObjectArrayToArrayObject(TO_JSON_STRING(files)) AS filesConverted
FROM sample_table
Is there a way to perform the same kind of task using native BigQuery statements?
Please note that:
The real data has more than 2 keys, but those are fixed in names
The length of the array is not fixed, can be 0, 1, 10, 20, ...

Answer 1

Below is for BigQuery Standard SQL
#standardSQL
WITH sample_table AS (
SELECT STRUCT<createdBy ARRAY<STRING>, fileName ARRAY<STRING>>(
["foo", "foo"],
["bar1", "bar2"]
) AS files
)
SELECT
ARRAY(
SELECT STRUCT(createdBy, fileName)
FROM t.files.createdBy AS createdBy WITH OFFSET
JOIN t.files.fileName AS fileName WITH OFFSET
USING(OFFSET)
) files
FROM `sample_table` t
with output
Row files.createdBy files.fileName
1 foo bar1
foo bar2