# $1623. 三人国家代表队
# https://leetcode.cn/problems/all-valid-triplets-that-can-represent-a-country/

# SQL架构
Create table If Not Exists SchoolA (student_id int, student_name varchar(20));
Create table If Not Exists SchoolB (student_id int, student_name varchar(20));
Create table If Not Exists SchoolC (student_id int, student_name varchar(20));
Truncate table SchoolA;
insert into SchoolA (student_id, student_name) values ('1', 'Alice');
insert into SchoolA (student_id, student_name) values ('2', 'Bob');
Truncate table SchoolB;
insert into SchoolB (student_id, student_name) values ('3', 'Tom');
Truncate table SchoolC;
insert into SchoolC (student_id, student_name) values ('3', 'Tom');
insert into SchoolC (student_id, student_name) values ('2', 'Jerry');
insert into SchoolC (student_id, student_name) values ('10', 'Alice');

# Write your MySQL query statement below
select
    sa.student_name as member_A,
    sb.student_name as member_B,
    sc.student_name as member_C
from
    SchoolA sa,
    SchoolB sb,
    SchoolC sc
where
    sa.student_id != sb.student_id
    and sb.student_id != sc.student_id
    and sa.student_id != sc.student_id
    and sa.student_name != sb.student_name
    and sb.student_name != sc.student_name
    and sa.student_name != sc.student_name;

# clean-up
drop table SchoolA;
drop table SchoolB;
drop table SchoolC;