表连接的难题在mycat中是不允许跨分片做表连接查询的
创建t_orders表
create table t_orders(
id int PRIMARY key,
customer_id int not null,
datetime TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
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use chinasoft;
create table t_customer(
id int primary key,
username varchar(200) not null,
sharding_id int not null
);
use chinasoft;
select * from t_customer;
insert into t_customer(id,username,sharding_id) values(1,"tom",101);
insert into t_customer(id,username,sharding_id) values(2,"jack",102);
insert into t_customer(id,username,sharding_id) values(3,"smith",105);
insert into t_customer(id,username,sharding_id) values(4,"lily",102);
insert into t_customer(id,username,sharding_id) values(5,"lucy",103);
insert into t_customer(id,username,sharding_id) values(6,"hanmeimei",104);
create table t_orders(
id int PRIMARY key,
customer_id int not null,
datetime TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
INSERT into t_orders(id,customer_id) values(1,1);
INSERT into t_orders(id,customer_id) values(2,1);
INSERT into t_orders(id,customer_id) values(3,1);
select c.username,o.id,o.datetime from t_customer c join t_orders o on c.id=o.customer_id;