Iterating Object of Array in Couchbase - arrays

Question

How to iterate Object of Array to get specific key value pair from JSON object. I am using Couchbase Server. Please suggest N1QL for Couchbase.
Below is my JSON format
{
"A":{
"B":{
"C": {
"D":[
{
"attr":[
{
"Name" : "abc"
}
],
"Name" : "outer"
}
], ​
"E":[
{
"attr":[
{
"Name" : "xyz"
}
],
"Name" : "outer1"
}
​]
}
}
}
}
​
Want to retrieve value for Name attribute inside each array of object C. Please note there are two fields with same name inside Array , so want to just access outer one. Key value pair inside C is dynamic.
Thanks in Advance!

Answer 1

If you really looking for all the names objects of path A.B.C
use the following expression
ARRAY v.Name FOR v WITHIN A.B.C WHEN v.Name IS NOT MISSING END
SELECT ARRAY v.Name
FOR v WITHIN d.A.B.C
WHEN v.Name IS NOT MISSING
END AS val
FROM [{ "A":{ "B":{ "C": { "D":[{"Name" : "test1", "state" : "state1"} ],
"E":[{"Name" : "test2", "state" : "state2"} ],
"F":[{"Name" : "test2", "state" : "state2"} ]
}
}
}
}
] AS d;
{
"val": [
"test1",
"test2",
"test2"
]
}
If you need to pick only some you need to have some other field present in that object consistently.
ARRAY v.Name FOR v WITHIN A.B.C WHEN v.Name IS NOT MISSING AND v.attr IS NOT MISSING END
SELECT ARRAY v.Name FOR v WITHIN d.A.B.C WHEN v.Name IS NOT MISSING AND v.attr IS NOT MISSING END
FROM [{ "A":{ "B":{ "C": { "D":[ { "attr":[ { "Name" : "abc" } ], "Name" : "outer" } ], "E":[ { "attr":[ { "Name" : "xyz" } ], "Name" : "outer1" } ] } } } }] AS d;
If you already know the predefined path (don't use recursive).
Construct ARRAY of the values of the dynamic field object. As the value is already ARRAY flatten by 1 level, Then iterate over ARRAY and get Name. If you need unique use ARRAY_DISTINCT()
ARRAY v.Name FOR v IN ARRAY_FLATTEN((ARRAY nv FOR n:nv IN d.A.B.C END),1) END
SELECT ARRAY v.Name FOR v IN ARRAY_FLATTEN((ARRAY nv FOR n:nv IN d.A.B.C END),1) END AS obj
FROM [{ "A":{ "B":{ "C": { "D":[ { "attr":[ { "Name" : "abc" } ], "Name" : "outer" } ], "E":[ { "attr":[ { "Name" : "xyz" } ], "Name" : "outer1" } ] } } } }] AS d;