mongo db: use $gte & $lte to find string dates by inputing only years

Question

I have an object that looks like this:

name:"Aachen"
mass:"21"
year:"1880-01-01T00:00:00.000"

I am trying to use $gte and $lte to find the entries that happened between certain YEARS.

I have tried this: db.collectionName.find({$expr: {$and: [{"year": {$gte:"1880"}}, {"year": {$lte: "1900"}} ]}})

but not getting any results

I think i need to parse the date to ISODate first and then destructure the year but not really sure how to perform the query.

Any guidance?

Thanks a lot

You should not store date values as strings, store Date values directly. — Wernfried Domscheit, Jan 17 '21 at 11:36

score 3 · Accepted Answer · answered Jan 16 '21 at 22:42

You cannot just query the year from a string. You have to transform the field to date and get the year from it. I would suggest using the aggregation framework for this as follows:

db.collectionName.aggregate([
    {
        $addFields: {
            justYear: {
                $year: {
                    $dateFromString: {
                        dateString: '$year',
                    },
                },
            },
        },
    },
    {
        $match: {
            justYear: {
                $gte: 1880,
                $lte: 1900,
            },
        },
    },
]);

Anything else let me know

mongo db: use $gte & $lte to find string dates by inputing only years

1 Answers1