兄弟们 有知道三个表怎么联合查询吗
A B C三个表, A是主表 B是A的副表 C是B的副表
冬天的太阳
- 发布:2022-01-19 14:36
- 更新:2023-02-25 18:57
- 阅读:460
const db = cloud.database()
const dbCmd = db.command
const $ = db.command.aggregate
let res = await db.collection('orders').aggregate()
.lookup({
from: 'books',
let: {
book_id: '$book'
},
pipeline: $.pipeline()
.match(
dbCmd.expr($.eq(['$_id', '$$book_id']))
)
.lookup({
from: 'authors',
let: {
author_id: '$author'
},
pipeline: $.pipeline()
.match(
dbCmd.expr($.eq(['$_id', '$$author_id']))
)
.done(),
as: 'authorList'
})
.done(),
as: 'bookList',
})
.end()
冬天的太阳 (作者)
jql语法
2022-01-19 14:55