Import JSON from CSV, grouping by multiple fields - json

Question

I would like to create a JSON with array of nested objects with a grouping for different fields.
This is the CSV and Iwould like to group it by sid, year and quarter (first three fields):
S4446B3,2020,202001,2,345.45
S4446B3,2020,202001,4,24.44
S4446B3,2021,202102,5,314.55
S6506LK,2020,202002,3,376.55
S6506LK,2020,202003,3,76.23
After splitting the CSV with the following I get an object for each record.
split("\n")
| map(split(","))
| .[0:]
| map({"sid" : .[0], "year" : .[1], "quarter" : .[2], "customer_type" : .[3], "obj" : .[4]})
But for each sid I would like to get an array of objects nested like this :
[
{
"sid" : "S4446B3",
"years" : [
{
"year" : 2020,
"quarters" : [
{
"quarter" : 202001,
"customer_type" : [
{
"type" : 2,
"obj" : "345.45"
},
{
"type" : 4,
"obj" : "24.44"
}
]
}
]
},
{
"year" : 2021,
"quarters" : [
{
"quarter" : 202102,
"customer_type" : [
{
"type" : 5,
"obj" : "314.55"
}
]
}
]
}
]
},
{
"sid" : "S6506LK",
"years" : [
{
"year" : 2020,
"quarters" : [
{
"quarter" : 202002,
"customer_type" : [
{
"type" : 3,
"obj" : "376.55"
}
]
},
{
"quarter" : 202003,
"customer_type" : [
{
"type" : 3,
"obj" : "76.23"
}
]
}
]
}
]
}
]

Answer 1

It'd be more intuitive if sid, year, quarter, etc. were to be key names. With -R/--raw-input and -n/--null-input options on the command line, this will do that:
reduce (inputs / ",")
as [$sid, $year, $quarter, $type, $obj]
(.; .[$sid][$year][$quarter] += [{$type, $obj}])
And, to get your expected output you can append these lines to the above program.
| .[][] |= (to_entries | map({quarter: .key, customer_type: .value}))
| .[] |= (to_entries | map({year: .key, quarters: .value}))
| . |= (to_entries | map({sid: .key, years: .value}))