MongoDB 与 SQL 语句映射关系(持续更新中)

前序：
无论是刚开始接触mongodb，还是接触了一段时间的老用户，每次想写一个DML语句都觉得有点费劲，
因为mongo的语法确实与RDMS不一样，所以为了方便我也为了方便后人，故整理一下他们之间的对应关系
（会结合官网文档以及自己的一些实践总结，会持续更新。。。）

SQL	MongoDB
database	database
table	collectioin
row	document
column	field
SELECT * FROM people	db.people.find()
SELECT id,        user_id,        status FROM people	db.people.find(    { },    { user_id: 1, status: 1 })
SELECT user_id, status FROM people	db.people.find(    { },    { user_id: 1, status: 1, _id: 0 })
SELECT * FROM people WHERE status = "A"	db.people.find(    { status: "A" })
SELECT user_id, status FROM people WHERE status = "A"	db.people.find(    { status: "A" },    { user_id: 1, status: 1, _id: 0 })
SELECT * FROM people WHERE status != "A" 10585	db.people.find(    { status: { $ne: "A" } })
SELECT * FROM people WHERE status = "A"     AND age = 50	db.people.find(    { status: "A",      age: 50 })
SELECT * FROM people WHERE status = "A"    OR age = 50	db.people.find(    { $or: [ { status: "A" } ,             { age: 50 } ] })
SELECT * FROM people WHERE age > 25	db.people.find(    { age: { $gt: 25 } })
SELECT * FROM people WHERE age > 25     AND   age <= 50	db.people.find(   { age: { $gt: 25, $lte: 50 } })
SELECT * FROM people WHERE user_id like "%bc%"	db.people.find( { user_id: /bc/ } ) -or- db.people.find( { user_id: { $regex: /bc/ } } )
SELECT * FROM people WHERE user_id like "bc%"	db.people.find( { user_id: /^bc/ } ) -or- db.people.find( { user_id: { $regex: /^bc/ } } )
SELECT * FROM people WHERE status = "A" ORDER BY user_id ASC	db.people.find( { status: "A" } ).sort( { user_id: 1 } )
SELECT COUNT(*) FROM people	db.people.count() -or- db.people.find().count()
SELECT COUNT(user_id) FROM people	db.people.count( { user_id: { $exists: true } } ) -or- db.people.find( { user_id: { $exists: true } } ).count()
SELECT COUNT(*) FROM people WHERE age > 30	db.people.count( { age: { $gt: 30 } } ) -or- db.people.find( { age: { $gt: 30 } } ).count()
SELECT DISTINCT(status) FROM people	db.people.distinct( "status" )
SELECT * FROM people  LIMIT 1 -or- SELECT TOP 1 * FROM people	db.people.findOne() -or- db.people.find().limit(1)
EXPLAIN SELECT * FROM people WHERE status = "A"	db.people.find( { status: "A" } ).explain()
UPDATE people SET status = "C" WHERE age > 25	db.people.updateMany(   { age: { $gt: 25 } },   { $set: { status: "C" } })
UPDATE people SET age = age + 3 WHERE status = "A"	db.people.updateMany(   { status: "A" } ,   { $inc: { age: 3 } })
DELETE FROM people WHERE status = "D"	db.people.deleteMany( { status: "D" } ) -or- db.people.remove({status:"D"})
DELETE FROM people	db.people.remove({})
SELECT state, SUM(pop) AS totalPop FROM zipcodes GROUP BY state HAVING totalPop >= (10*1000*1000)	db.zipcodes.aggregate( [    { $group: { _id: "$state", totalPop: { $sum: "$pop" } } },    { $match: { totalPop: { $gte: 10*1000*1000 } } } ] )