1，把表中某一列的内容合并为一行
select province,CONCAT(‘[\"全部\",\"‘,GROUP_CONCAT(city ORDER BY cityID separator ‘\"\,\"‘),‘\"]‘) as group1 from hat_city a LEFT JOIN hat_province b on a.father=b. provinceID GROUP BY father
ORDER BY cityID：根据指定字段排序，再合并
separator：指定分隔符，本文分隔符为（","）
原文：http://www.cnblogs.com/vijayfly/p/6023610.html