How can I get total count of likes, dislikes and shares for each book Id from a table in mongodb usi-CodePudding

I have a table named histories. here is a sample of documents,

{ "_id": "6354e4210490e6f3dd109fb7", "type": "like", "bookId": "6329af1b1c67cc8eaf26fe42", "userId": "635122ea40ef5d60e653fc9e", "createdAt": "2022-10-23T06:50:09.166Z", "updatedAt": "2022-10-23T06:50:09.166Z", "__v": 0 },

{ "_id": "6354e4210490e6f3dd109fb9", "type": "share", "bookId": "6322db5464c70448ad0282d4", "userId": "6301e9f243719de7e0637acf", "createdAt": "2022-10-23T06:50:09.167Z", "updatedAt": "2022-10-23T06:50:09.167Z", "__v": 0 }

now i have to show a list of distinct bookId with its total likes, shares and dislikes count using aggregate in mongodb..

CodePudding user response：

You can try with

db.histories.aggregate([
    {
        $group: {
            _id: "$bookId" ,
            likes: {
                "$sum": { $cond: { if: { "$eq": ["$type", "like"]}, then: 1, else: 0 }}
            },
            dislikes: {
                "$sum": { $cond: { if: { "$eq": ["$type", "dislike"]}, then: 1, else: 0 }}
            },
            shares: {
                "$sum": { $cond: { if: { "$eq": ["$type", "share"]}, then: 1, else: 0 }}
            },
        }
    },
])