Join 3 or more documents

I have 3 documents in a single bucket named “test_bucket” as follows:
user document :
{
"_id": “5fe42874-f19c-4592-bdad-ae5f88872246”,
“title”: “users”,
“userId”: “user_123”,
“aadharNo”: “334455667754”,
“panNo”: “2232344433”,
“firstName”: “jane”,
“lastName”: “george”
}

{
"_id": “5fe42874-f19c-4592-bdad-ae5f88872246”,
“title”: “users”,
“userId”: “user_1234”,
“aadharNo”: “3674556673”,
“panNo”: “25323788933”,
“firstName”: “jaise”,
“lastName”: “mariya”
}

notification document :
{
"_id": “559c82d3-dcf8-45e4-b6b8-89d03a73ad2d”,
“title”: “notifications”,
“userId”: "user_123"
“bizId”: “business_123”,
“nType”: “NB”,
“nStatus”: “P”,
“actionType”: 3

}

{
"_id": “559c82d3-dcf8-45e4-b6b8-89d03a73ad2d”,
“title”: “notifications”,
“userId”: "user_1234"
“bizId”: “business_1234”,
“nType”: “NB”,
“nStatus”: “P”,
“actionType”: 3

}

business document
{
"_id": “6b3e6d37-a769-437b-b343-c0513b4d2a79”,
“title”: “business”,
“bizId”: “business_123”,
“userId”: "user_123"
“Name”: “business2”,
“sName”: “dd”,
“website”: “www.bus2.com

}

{
"_id": “6b3e6d37-a769-437b-b343-c0513b4d2a79”,
“title”: “business”,
“bizId”: “business_1234”,
“userId”: "user_1234"
“Name”: “business2”,
“sName”: “dd”,
“website”: “www.bus2.com

}
i have only bizId with me,using bizId how to fetch complete details from user and notification document

you can only join on document keys.
for example
notification document :
{
"_id": “559c82d3-dcf8-45e4-b6b8-89d03a73ad2d”,
“title”: “notifications”,
“userId”: “user_123”
“bizId”: “business_123”,
“nType”: “NB”,
“nStatus”: “P”,
“actionType”: 3

}

you should use user_123 as user document’s key, and business_123 as business document’s key. then you can join the document by key.

for example

insert into default  (key, value) values ("user_123", {
"title": "users",
"userId": "user_123",
"aadharNo": "334455667754",
"panNo": "2232344433",
"firstName": "jane",
"lastName": "george"
}), 
("user_1234", {
"title": "users",
"userId": "user_1234",
"aadharNo": "3674556673",
"panNo": "25323788933",
"firstName": "jaise",
"lastName": "mariya"
}), 
("notifications_123", {
"title": "notifications",
"userId": "user_123",
"bizId": "business_123",
"nType": "NB",
"nStatus": "P",
"actionType": 3

}), 
("notifications_456", {
"title": "notifications",
"userId": "user_1234",
"bizId": "business_1234",
"nType": "NB",
"nStatus": "P",
"actionType": 3

}),
("business_123", {
"title": "business",
"bizId": "business_123",
"userId": "user_123",
"Name": "business2",
"sName": "dd",
"website": "www.bus2.com"

}),
("business_1234", {
"title": "business",
"bizId": "business_1234",
"userId": "user_1234",
"Name": "business2",
"sName": "dd",
"website": "www.bus2.com"
});

you can use the following N1QL

SELECT n.*,u.* 
  FROM default n JOIN default u ON KEYS n.userId 
 WHERE n.bizId == "business_123"

to fetch complete details from user and notification document using bizId.