MySQL-根据团队成员资格返回多个用户

编程问答 2022-07-25

问题描述

我希望返回被请求用户（通过对users的{​​{1}}值进行硬编码模拟）所组成的teams成员的所有uid。我正在尝试通过使用联接表user1来实现这一点，但是只能以查询结束，而不是返回比我要找的东西还要多的东西。

DB Fiddle Link

在查询输出（查询＃3）中，我希望不看到teams_members，因为它们不是user3或team1（唯一的）的一部分team2所属的团队。

设置：

user1

查询（为上下文添加了其他查询）：

CREATE TABLE users (
  uid INT,name TEXT
);
INSERT INTO users (uid,name) VALUES (1,"user1");
INSERT INTO users (uid,name) VALUES (2,"user2");
INSERT INTO users (uid,name) VALUES (3,"user3");

CREATE TABLE teams (
  tuid INT,name TEXT
);
INSERT INTO teams (tuid,'team1');
INSERT INTO teams (tuid,'team2');
INSERT INTO teams (tuid,'team3');

CREATE TABLE teams_members (
  uid INT,tuid INT,role TEXT
);
INSERT INTO teams_members (uid,tuid,role) VALUES (1,1,'owner');
INSERT INTO teams_members (uid,2,role) VALUES (2,role) VALUES (3,3,'owner');

我如何只退回# Get user SELECT * FROM users WHERE uid = 1; # Get teams the user is part of SELECT t.tuid,t.name FROM teams t LEFT JOIN teams_members tm ON t.tuid = tm.tuid WHERE uid = 1; # Get team members present for all teams <<<<<<< Query in question SELECT u.uid,u.name FROM users u LEFT JOIN teams_members tm ON u.uid = tm.uid LEFT JOIN teams t ON tm.tuid = t.tuid WHERE tm.uid = u.uid; 所属团队中的 users？

解决方法

您的第二个查询就是您所需要的。用它来获取表用户的数据：

 ffmpeg -i FullScreenVidio.mp4 -i PictureWindow.mp4 -filter_complex "[1]scale=iw/2.15:ih/2.15 [pip]; [0][pip] overlay=25:25" -profile:v main -level 3.1 -b:v 440k -ar 44100 -ab 128k -s 1920x1080 Result.mp4 

=vf eq=brightness=0.25:contrast=1.5:saturation=1.5

这是演示：

DEMO

,

如何只返回出现在user1所在团队中的用户？

一种方法使用exists：

select u.*
from users u
where exists (select 1
              from teams_members tm1 join
                   teams_members tm2
                   on tm1.tuid = tm2.tuid  -- same team
              where tm1.uid = 1 and        -- team has user 1
                    tm2.uid = u.uid        -- team has user in outer query
             );
mysqlsqlsql