Is it possible to do an OR in the $match?
I mean something like this:
db.articles.aggregate(
{ $or: [ $match : { author : "dave" }, $match : { author : "john" }] }
);
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3 Answers
$match: { $or: [{ author: 'dave' }, { author: 'john' }] }
Like so, since the $match operator just takes what you would normally put into the find() function
Comments
In this particular case, where you are $or-ing the same field, the $in operator would be a better choice, also because it increases readability:
$match: {
'author': {
$in: ['dave','john']
}
}
According to the MongoDB docs, using $in is recommended in this case:
$or versus $in
When using $or with <expressions> that are equality checks for the value of the same field, use the $in operator instead of the $or operator.
https://docs.mongodb.com/manual/reference/operator/query/or/#or-versus-in
7 Comments
Mark Gibaud
According to Mongo docs, this "most effective" way of doing it for equality comparisons such as your example. See docs.mongodb.org/manual/reference/operator/query/or/#_S_or%22
Chenna V
The $in is the way to go
Paul Shapiro
I believe $or is not an aggregation operator.
Amol M Kulkarni
@PaulShapiro: I hope you did not down voted because of this. For all please consider commenting the reason before down-voting it helps everyone. Here is the reference Boolean Aggregation Operators -> $or
Paul Shapiro
Your answer is not correct, and as you can see, I already commented explaining where and how the answer is incorrect.
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$match : {
$or: [
{
$expr: {
$ne: ["$community", ObjectId(id)]
}
},
{
community: {
$exists: false
}
}
]
}
1 Comment
Community
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