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  1. Core Server
  2. SERVER-21469

$lookup is not working in case of the localField is array

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    • Type: Icon: Bug Bug
    • Resolution: Duplicate
    • Priority: Icon: Major - P3 Major - P3
    • None
    • Affects Version/s: 3.2.0-rc2
    • Component/s: Aggregation Framework
    • Labels:
      None
    • Environment:
      Windows7 64
    • Windows
    • Hide 
      -----inventory--------
/* 1 */
{
    "_id" : 1,
    "sku" : "abc",
    "description" : "product 1",
    "instock" : 120
}

/* 3 */
{
    "_id" : 3,
    "sku" : "ijk",
    "description" : "product 3",
    "instock" : 60
}
/* 5 */
{
    "_id" : 5,
    "sku" : null,
    "description" : "Incomplete"
}

/* 6 */
{
    "_id" : 6
}
----Orders collection----
/* 1 */
{
    "_id" : 1,
    "item" : [ 
        {
            "ID" : "abc"
        }, 
        {
            "ID" : "jkl"
        }
    ],
    "price" : 12,
    "quantity" : 2
}

/* 2 */
{
    "_id" : 2,
    "item" : [ 
        {
            "ID" : "jkl"
        }
    ],
    "price" : 20,
    "quantity" : 1
}

/* 3 */
{
    "_id" : 3
}
----Aggregate function ---
db.orders.aggregate([
    {
      $lookup:
        {
          from: "inventory",
          localField: "item.ID",
          foreignField: "sku",
          as: "inventory_docs"
        }    
   }
])
      Show
      -----inventory-------- /* 1 */ { "_id" : 1, "sku" : "abc", "description" : "product 1", "instock" : 120 } /* 3 */ { "_id" : 3, "sku" : "ijk", "description" : "product 3", "instock" : 60 } /* 5 */ { "_id" : 5, "sku" : null, "description" : "Incomplete" } /* 6 */ { "_id" : 6 } ----Orders collection---- /* 1 */ { "_id" : 1, "item" : [ { "ID" : "abc" }, { "ID" : "jkl" } ], "price" : 12, "quantity" : 2 } /* 2 */ { "_id" : 2, "item" : [ { "ID" : "jkl" } ], "price" : 20, "quantity" : 1 } /* 3 */ { "_id" : 3 } ----Aggregate function --- db.orders.aggregate([ { $lookup: { from: "inventory", localField: "item.ID", foreignField: "sku", as: "inventory_docs" } } ])

      When use $lookup to refer an array of keys to other collection. it give unexpected result.

            Assignee:
            charlie.swanson@mongodb.com Charlie Swanson
            Reporter:
            mahawas Mohamed Hawwas
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              Created:
              Updated:
              Resolved: