mongodb query to get related data from relational collections

mongodb query to get related data from relational collections - mongodb

I have 6 collections:
A,B,C,D,E and F
the A collection has many relations with B collection:
one side is A collection.
many side is B collection.
collection A with coll_B_list field is connected to collection B.
collection B with coll_A field is connected to collection A.
collection A:
[
{id:"a1", coll_B_list:["b1", "b2", "b3", "b4"]},
{id:"a2", coll_B_list:["b5", "b6", "b7", "b8"]}
]
the B collection has one relation with collections C,D,E and F.
collection B with the coll_C field is connected to collection C.
collection B with the coll_D field is connected to collection D.
collection B with the coll_E field is connected to collection E.
collection B with the coll_F field is connected to collection F.
the collections C, D, E and F with the coll_B field are connected to collection B.
collection B:
[
{id:"b1", date:"2020-06-01", coll_A:"a1", coll_C:"c1", coll_D:"d2"},
{id:"b2", date:"2020-07-01", coll_A:"a1", coll_C:"c2"},
{id:"b3", date:"2020-05-01", coll_A:"a1", coll_C:"c3", coll_D:"d3", coll_E:"e1", coll_F:"f1"},
{id:"b4", date:"2020-08-01", coll_A:"a1", coll_C:"c4", coll_D:"d1", coll_E:"e2"},
{id:"b5", date:"2020-04-01", coll_A:"a2", coll_C:"c5", coll_D:"d4", coll_E:"e3"},
{id:"b6", date:"2020-01-01", coll_A:"a2", coll_C:"c6", coll_D:"d5", coll_E:"e4", coll_F:"f2"},
{id:"b7", date:"2020-10-01", coll_A:"a2", coll_C:"c7"},
{id:"b8", date:"2020-09-01", coll_A:"a2", coll_C:"c8", coll_D:"d6"}
]
collection C:
[
{id:"c1", coll_B:"b1", value:"v1"},
{id:"c2", coll_B:"b2", value:"v2" },
{id:"c3", coll_B:"b3", value:"v3" },
{id:"c4", coll_B:"b4", value:"v4" },
{id:"c5", coll_B:"b5", value:"v5" },
{id:"c6", coll_B:"b6", value:"v6" },
{id:"c7", coll_B:"b7", value:"v7" },
{id:"c8", coll_B:"b8", value:"v8" }
]
collection D:
[
{id:"d1", coll_B:"b4", value:"v9" },
{id:"d2", coll_B:"b1", value:"v10" },
{id:"d3", coll_B:"b3", value:"v11" },
{id:"d4", coll_B:"b5", value:"v12" },
{id:"d5", coll_B:"b6", value:"v13" },
{id:"d6", coll_B:"b8", value:"v14" }
]
collection E:
[
{id:"e1", coll_B:"b3", value:"v15" },
{id:"e2", coll_B:"b4", value:"v16" },
{id:"e3", coll_B:"b5", value:"v17" },
{id:"e4", coll_B:"b6", value:"v18" }
]
collection F:
[
{id:"f1", coll_B:"b3", value:"v19" },
{id:"f2", coll_B:"b6", value:"v20" }
]
I want Query that its result be like this:
coll_B_list field should :
sorted descending base on date field.
in the collections C,D,E and F :
- if exist related collection then show that
- else show the nearest collection
Result:
[
{
id:"a1",
coll_B_list:[
{
id:"b4",
date:"2020-08-01",
coll_C:{id:"c4", value:"v4"},
coll_D:{id:"d1", value:"v9"},
coll_E:{id:"e2", value:"v16"},
coll_F:{id:"f1", value:"v19"} // doesnt exist so get the nearest value
},
{
id:"b2",
date:"2020-07-01",
coll_C:{id:"c2", value:"v2"},
coll_D:{id:"d2", value:"v10"}, // doesnt exist so get the nearest value
coll_E:{id:"e1", value:"v15"}, // doesnt exist so get the nearest value
coll_F:{id:"f1", value:"v19"} // doesnt exist so get the nearest value
},
{
id:"b1",
date:"2020-06-01",
coll_C:{id:"c1", value:"v1"},
coll_D:{id:"d2", value:"v10"},
coll_E:{id:"e1", value:"v15"}, // doesnt exist so get the nearest value
coll_F:{id:"f1", value:"v19"} // doesnt exist so get the nearest value
},
{
id:"b3",
date:"2020-05-01",
coll_C:{id:"c3", value:"v3"},
coll_D:{id:"d3", value:"v11"},
coll_E:{id:"e1", value:"v15"},
coll_F:{id:"f1", value:"v19"} // doesnt exist so get the nearest value
}
]
},
{
id:"a2",
coll_B_list:[
{
id:"b7",
date:"2020-10-01",
coll_C:{id:"c7", value:"v7"},
coll_D:{id:"d6", value:"v14"}, // doesnt exist so get the nearest value
coll_E:{id:"e3", value:"v17"}, // doesnt exist so get the nearest value
coll_F:{id:"f2", value:"v20"} // doesnt exist so get the nearest value
},
{
id:"b8",
date:"2020-09-01",
coll_C:{id:"c8", value:"v8"},
coll_D:{id:"d6", value:"v14"},
coll_E:{id:"e3", value:"v17"}, // doesnt exist so get the nearest value
coll_F:{id:"f2", value:"v20"} // doesnt exist so get the nearest value
},
{
id:"b5",
date:"2020-04-01",
coll_C:{id:"c5", value:"v5"},
coll_D:{id:"d4", value:"v12"},
coll_E:{id:"e3", value:"v17"},
coll_F:{id:"f2", value:"v20"} // doesnt exist so get the nearest value
},
{
id:"b6",
date:"2020-01-01",
coll_C:{id:"c6", value:"v6"},
coll_D:{id:"d5", value:"v13"},
coll_E:{id:"e4", value:"v18"},
coll_F:{id:"f2", value:"v20"}
}
]
}
]
COLLECTIONS IN MONGOPLAYGROUND
NESTED $lookup in MONGOPLAYGROUND
NESTED $lookup in MONGOPLAYGROUND That Sorted

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