SQL查询数据后在连成字符串方法

CREATE TABLE tb
(
user_id		INT,
type_id		TINYINT
);

INSERT INTO tb (user_id, type_id) VALUES (1,11);
INSERT INTO tb (user_id, type_id) VALUES (1,12);
INSERT INTO tb (user_id, type_id) VALUES (1,13);
INSERT INTO tb (user_id, type_id) VALUES (1,14);
INSERT INTO tb (user_id, type_id) VALUES (1,15);