Nested $and or grouped $and in MongoDB -

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consider following document:

{     "_id" : objectid("5130f9a677e23b11503fee55"),     "itemtype" : "bicycle"      "attributes" : [{          "attributename" : "spare tire",          "attributevalue" : "1"      }, {          "attributename" : "with helmet?",          "attributevalue" : "0"      }, {          "attributename" : "number of locks",          "attributevalue" : "1"      }] }

how write query bicycles spare tire , no helmet?

i tried following doesn't give me want.

{  "$and" :  [      { "itemtype" : "bicycle" },      { "$and":          [{ "attributes.attributename" : "with helmet?" },           { "attributes.attributevalue" : "0" }    ]},     { "$and":          [{ "attributes.attributename" : "spare tire" },           { "attributes.attributevalue" : "1" }    ]} ]}

it seems long there value matches attributes.attributevalue - regardless of accompanying attributes.attributename - returns document. it's having query:

{  "$and" :  [      { "itemtype" : "bicycle" },                        //true     { "attributes.attributename" : "with helmet?" },   //true      { "attributes.attributename" : "spare tire" },     //true     { "attributes.attributevalue" : "0" },             //any     { "attributes.attributevalue" : "1" }              //any ]}

i believe looking $elemmatch here, whereby makes sure correspoding attributename , attributevalue in same element of multi-value field ( http://docs.mongodb.org/manual/reference/operator/elemmatch/ ):

{     itemtype: 'bicycle',      $and:[         {"attributes": {$elemmatch:{attributename: 'with helmet?', attributevalue: 0 }}},         { //next match }     ] }

try that


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