mysql - 如何使用子查询显示来自多个表的列名

Question

我创建了下表并插入了这些值:

create table customer (cid int, cname varchar(25), email varchar(25), phone int, status varchar(25), primary key (cid));
create table accounts( cid int, account int, atype varchar(25), balance int, foreign key(cid) references customer(cid));
create table address( cid int, street varchar(25), city varchar(25), country varchar(25), foreign key(cid) references customer(cid));




insert into customer values (101,'A', 'a@gmail.com', 99,'active');
insert into accounts values (101, 123, 'SA', 1000);
insert into address values (101, 'HMT','Blore','India');

insert into customer values (102,'B', 'b@gmail.com', 199,'active');
insert into accounts values (102, 123, 'CA', 2000);
insert into address values (102, 'Jayanagar','Blore','India');

我的目标是显示状态为活跃的客户的 cname、帐户和余额。

我试过使用这个编写查询:(我无法使用这个打印 cname 列)但它显示了其余部分。

select account, balance
from accounts
where cid in (select cid from customer where status = 'active');

这不起作用:

select cname, account, balance
from  customer, accounts
where cid in (select cid from customer where status = 'active');

Answer 1

一种可能的方法是在公共(public)客户 ID 上连接两个表。

SELECT c.cname,
       a.account,
       a.balance
       FROM customer c
            LEFT JOIN accounts a
                      ON a.cid = c.cid
       WHERE c.status = 'active';