How does mongodb filter the subarrays of a two-dimensional array?

  mongodb, question

The following data structure:
Join me and have a fruit’s Document, which reads:

{
 name: 'apple',
 menu: [
 {
 Title:' with pears'
 },
 {
 Title:' with strawberries'
 }
 ]
 },
 {
 name: 'orange',
 menu: [
 {
 Title:' with pears'
 },
 {
 Title:' with strawberries'
 }
 ]
 }

I want to searchPearWhen, get

{
 name: 'apple',
 menu: [
 {
 Title:' with pears'
 }
 ]
 },
 {
 name: 'orange',
 menu: [
 {
 Title:' with pears'
 }
 ]
 }

In other words, how to clean the sub-arrays of the two-dimensional array?

If title doesn’t repeat, simply do the mapping

Db.test.find ({menu.title ":'with pears' }, {name: 1, "menu.$": 1})

But $ will only give you the first matching array element, so if title is duplicated, you need to use thefilterOperator. For specific usage, refer to the examples in the document.

Related Posts: