左连接的表中有多条数据如何只取一条(最大或最小)

表a,有字段id,表b有字段cid,create_time,a表中的id对应b表中的cid,a表左连接b表，现在a中一条数据对应b中多条数据,如何只取b表中create_time最大的一条 ?

CREATE TABLE a (id INT);
CREATE TABLE B (cid INT, create_timeDATETIME);
INSERT INTO a SELECT 1 UNION SELECT 2;
INSERT INTO b SELECT 1,'2010-10-01'
 UNION SELECT 1,'2010-10-02'
 UNION SELECT 2,'2010-10-01'
 UNION SELECT 2,'2010-10-02'
 UNION SELECT 2,'2010-10-03';
 
SELECT * FROM a LEFT JOIN (SELECT MAX(create_time)AS create_time,cid FROM b GROUP BY cid) b1
ON b1.cid = a.id;