我正在搜索mongodb,查看从A到B的所有消息以及从B到A的所有陈述。这样我就可以进行对话
从:人A AND 到:personB
或
从:B人 AND 到personA
// Create a conversation
db.collection('messages', function (err, collection) {
collection.find(
{ // how do I turn this $and into a two nested $and statements inside $or?
$and: [{
receiver: new BSON.ObjectID(req.user._id)
}, {
sender: new BSON.ObjectID(req.body.sender)
}]
}
).sort({
date: -1
}).toArray(function (err, docs) {
console.log(docs);
})
});
答案 0 :(得分:3)
答案应该是这样的:
db.collection('messages', function (err, collection) {
collection.find(
{
$or : [
{$and: [{
receiver: new BSON.ObjectID(req.user._id)
}, {
sender: new BSON.ObjectID(req.body.sender)
}]},
{$and: [{
receiver: new BSON.ObjectID(req.body.sender)
}, {
sender: new BSON.ObjectID(req.user._id)
}]},
]
}
).sort({
date: -1
}).toArray(function (err, docs) {
console.log(docs);
})
});
答案 1 :(得分:2)
我不熟悉您正在调用的collection
函数,并且不知道您所指的req
对象是什么,所以请尽量回答我的答案。< / p>
在我看来,你做的比实际需要的要复杂得多。您的$and
语句非常简单,不需要$and
关键字:
collection.find({
receiver: req.user._id,
sender: req.body.sender
})
现在,$and
和$or
的工作方式完全相同:它们采用一系列对象。所以,让我们写下我认为您的查询意图:
collection.find({
$or: [{
receiver: req.user._id,
sender: req.body.sender
}, {
receiver: req.body.sender,
sender: req.user_id
}]
})
答案 2 :(得分:1)
试试这个
db.collection('messages', function (err, collection) {
collection.find(
{ $or: [
{$and: [{ receiver: new BSON.ObjectID(req.user._id)}, {sender: new BSON.ObjectID(req.body.sender)}]}
{$and: [{ receiver: new BSON.ObjectID(req.body.sender)}, {sender: new BSON.ObjectID(req.user._id)}]}
]
}).sort({
date: -1
}).toArray(function (err, docs) {
console.log(docs);
}) });