Query records

Call the findOne method to query the name of the record with the lowest age value greater than 18.

projection: { name: 1 } specifies that only the name field is returned. In this context, a value of 1 includes the field, and a value of 0 excludes it.

sort: { age: 1 } sorts the query results in ascending order. A value of 1 specifies ascending order, and -1 specifies descending order.

mpserverless.db.collection('users')
  .findOne({
    age: { $gt: 18 }
  }, {
    projection: { name: 1 },
    sort: { age: 1 }
  })
  .then(res => { })
  .catch(console.error);

Call the find method to query the name of all records with an age greater than 18. The results are returned in ascending order.

mpserverless.db.collection('users')
  .find({
    age: { $gt: 18 }
  }, {
    projection: { name: 1 },
    sort: { age: 1 }
  })
  .then(res => { })
  .catch(console.error);

Call the findOneAndDelete method to find and delete the record with the highest age value that is less than 18.

mpserverless.db.collection('users')
  .findOneAndDelete({
    age: { $lt: 18 }
  }, {
    sort: { age: -1 }
  })
  .then(res => { })
  .catch(console.error);

Call the findOneAndReplace method to find and replace a document whose name is zhangsan.

mpserverless.db.collection('users')
  .findOneAndReplace({
    name: "john"
  }, {
    $set: {
      name: "lisa",
      age: 20
    }
  })
  .then(res => { })
  .catch(console.error);

Call findOneAndUpdate to update the age field of a record where the name is zhangsan.

mpserverless.db.collection('users')
    .findOneAndUpdate({
        name: "john"
    },
    {
    $set: {
        age: 18
        }
    })
    .then(res => {})
    .catch(console.error);

Call the findOne method to query the name of the record with the lowest age value greater than 18.

projection: { name: 1 } specifies that only the name field is returned. In this context, a value of 1 includes the field, and a value of 0 excludes it.

sort: { age: 1 } sorts the query results in ascending order. A value of 1 specifies ascending order, and -1 specifies descending order.

'use strict';

module.exports = async function (ctx) {
  return await ctx.mpserverless.db.collection('users')
    .findOne({
      age: { $gt: 18 }
    }, {
      projection: { name: 1 },
      sort: { age: 1 }
    });
};                    

Call the find method to query the name of all records with an age greater than 18. The results are returned in ascending order.

'use strict';

module.exports = async function (ctx) {
  return await ctx.mpserverless.db.collection('users')
    .find({
      age: { $gt: 18 }
    }, {
      projection: { name: 1 },
      sort: { age: 1 }
    });
};

Call the findOneAndDelete method to find and delete the record with the highest age value that is less than 18.

'use strict';

module.exports = async function (ctx) {
  return await ctx.mpserverless.db.collection('users')
    .findOneAndDelete({
      age: { $lt: 18 }
    }, {
      sort: { age: -1 }
    });
};                    

You can call the findOneAndReplace method to find and replace a document whose name field is zhangsan.

'use strict';

module.exports = async function (ctx) {
  return await ctx.mpserverless.db.collection('users')
    .findOneAndReplace({
      name: "john"
    },{
      $set: {
        name: "lisa",
        age: 20
      }
    });
}; 

Call findOneAndUpdate to update the age field of a record where the name field is zhangsan.

'use strict';

module.exports = async function (ctx) {
  return await ctx.mpserverless.db.collection('users')
    .findOneAndUpdate({
        name: "john"
    },
      {
        $set: {
          age: 18
        }
      });
};