How to use JSONiq for JSON - json

Question

The question is to write a JSONiq FLWOR expression that can display the name of the products which their price are at least 3.
I have tried the answers provided on How to run JSONiq from JSON with try.zorba.io but that's not the answers that i expect. Beside that, I also tried a lot of JSON FLWOR expression but still getting errors in try.zobia.io. This is my JSON file.
{
"supermarket": {
"visit": [ {
"_type": "bought",
"date": "March 8th, 2019",
"product": [ {
"name": "Kit Kat",
"amount": 3,
"cost": 3.5
},
{
"name": "Coca Cola",
"amount": 2,
"cost": 3
},
{
"name": "Apple",
"amount": "Some",
"cost": 5.9
}
]
},
{
"_type": "planning",
"product": [{
"name": "Pen",
"amount": 2
},
{
"name": "Paper",
"amount": "One ream"
}
]
}
]
}
}
This is my current JSONiq expression.
jsoniq version "1.0";
let $a := { (: my JSON file :) }
for $x in $a.supermarket.visit
let $y = $x.product()
where $y.price >= "3.0"
return $y.name
The final output should be Kit Kat, Coca Cola and Apple. I would appreciate some helps for my JSON file or JSONiq.

Answer 1

visit also is an array, so you need the parenthesis to get to the individual visits in the for. This
jsoniq version "1.0";
let $data := { (: my JSON file :) }
for $visit in $data.supermarket.visit()
for $product in $visit.product()
where $product.cost ge 3
return $product.name
would return
Kit Kat Coca Cola Apple
Since the above produces a sequence, you can use it anywhere where sequences are allowed.
let $data := { (: my JSON file :) }
return string-join(
for $visit in $data.supermarket.visit()
for $product in $visit.product()
where $product.cost ge 3
return $product.name
, ", ")
Result:
Kit Kat, Coca Cola, Apple
Of course this would work as well:
for $product in $data.supermarket.visit().product()
where $product.cost ge 3
return $product.name