A technique for filtering mongo data where a field exists

In business development, there may be a judgment whether there is a certain field in Mongo, and the existence of this field can be taken out of the data, you can use the following skills:

Suppose mongo’s user_info table stores three items of data as follows:

{
    uid:1,
    sex:1,
},
{
    uid:2,
    sex:0,
    resume:{
        name:"test1",
        desc:"this is test1"
    }
},
{
    uid:3,
    sex:1,
    resume:{
        name:"test1",
        desc:"this is test1"}}Copy the code

Suppose our requirements are: Select ‘resume.name’ from ‘user_info’ where ‘resume.name’ does not exist. If it exists, the data is ideal. The query method is as follows:

  db.user_info.aggregate([
    {
        $match: {$or: [{"resume.name": {$regex:""}}}}]Copy the code

If the resume.name field does not match the resume.name field, the data will not be returned