MySQL写查询，求助？

Question

表 T_USER

表 T_ROLE

我想查询的结果为：

以下为建表及数据脚本

drop table if exists T_USER;
CREATE TABLE T_USER(
USER_ID INT,
USER_NAME VARCHAR(25)
);
INSERT INTO T_USER VALUES(1,'USER_A');
INSERT INTO T_USER VALUES(2,'USER_B');

drop table if exists T_ROLE;
CREATE TABLE T_ROLE(
USER_ID INT,
USER_ROLE VARCHAR(25)
);
INSERT INTO T_ROLE VALUES(1,'ROLE_1');
INSERT INTO T_ROLE VALUES(1,'ROLE_2');

求助，如何实现

Answer 1

SELECT u.USER_ID, r.USER_ROLE, u.USER_NAME FROM T_USER u LEFT JOIN T_ROLE r ON u.USER_ID = r.USER_ID;