如果觉得 Mongodb 语句不太好理解,可以和 SQL 语句进行对比,学起来要容易很多。
查询(find)
查询所有结果
select * from article db.article.find()
指定返回哪些键
select title, author from article db.article.find({}, {"title": 1, "author": 1})
where条件
select * from article where title = "mongodb" db.article.find({"title": "mongodb"})
and条件
select * from article where title = "mongodb" and author = "god" db.article.find({"title": "mongodb", "author": "god"})
or条件
select * from article where title = "mongodb" or author = "god" db.article.find({"$or": [{"title": "mongodb"}, {"author": "god"}]})
比较条件
select * from article where read >= 100; db.article.find({"read": {"$gt": 100}}) > $gt(>)、$gte(>=)、$lt(<)、$lte(<=) select * from article where read >= 100 and read <= 200 db.article.find({"read": {"$gte": 100, "lte": 200}})
in条件
select * from article where author in ("a", "b", "c") db.article.find({"author": {"$in": ["a", "b", "c"]}})
like
select * from article where title like "%mongodb%" db.article.find({"title": /mongodb/})
count
select count(*) from article db.article.count()
不等于
select * from article where author != "a" db.article.find({ "author": { "$ne": "a" }})
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