db.inventory.find( { $and: [ { price: { $ne: 1.99 } }, { price: {$exists: true } } ] } )
this query selects all documents in the collection inventory, provided that price is not equal to 1.99 and the price field exists. My problem is that I now need to set {$ne: 1.99} after price as a variable instead of writing it out directly. But I found that if:
var obj = {},
db.inventory.find( { $and: [ { price: obj }, { price: { $exists: true } }] } )
query statement is invalid. I would like to ask the condition in the query statement must be written directly, can not be put into the variable? Is there any solution?