jq, search for a 'sections' basing on a value of an attribute - unique

Question

I am new in this stuff,
I have input json:
{
"2017-09-15": {
"key": "stops",
"node": {
"lastUpdate": "2017-09-15 05:15:26",
"stops": [
{
"stopId": 11000,
"stopCode": null,
"stopName": null,
"stopShortName": "1000",
"stopDesc": "Tom Tail",
"subName": "1000",
"zoneId": null,
"zoneName": null,
"stopUrl": "",
"locationType": null,
"parentStation": null,
"stopTimezone": "",
"wheelchairBoarding": null,
"virtual": null,
"nonpassenger": null,
"depot": null,
"ticketZoneBorder": null,
"onDemand": null,
"activationDate": "2017-09-14"
},
{
"stopId": 1100,
"stopCode": "04",
"stopName": "One Three",
"stopShortName": "1100",
"stopDesc": "Big Wall",
"subName": "04",
"zoneId": 1,
"zoneName": "Demo2",
"stopUrl": "",
"locationType": null,
"parentStation": null,
"stopTimezone": "",
"wheelchairBoarding": null,
"virtual": 0,
"nonpassenger": 0,
"depot": 0,
"ticketZoneBorder": 0,
"onDemand": 0,
"activationDate": "2017-09-24"
}
]
}
}
}
I can get all stops by filter:
jq -r '.[].node.stops' json
but how to search for a specific stop, for example basing on stopDescr - exact name or containing a string?
thx.

Answer 1

You're on the right track ...
.[].node.stops[] | select(.stopDesc == "Big Wall")
unique
Regarding the supplementary question:
1) sort and unique both expect arrays as input
2) calling unique obviates the need to call sort
3) unique produces an array, so you might want to use unique[]
4) One way to convert a stream of (JSON) values to an array is to wrap the expression producing the stream in square brackets.
Here is an example:
[.[].node.stops[] | select(.stopDesc == "Big Wall") | .zoneName]
| unique