mysql跨库查询及批量修改

SELECT a.kefu_id,b.kefu_id FROM roncoo_education_course.`order_info` a JOIN roncoo_education_user.`user_ext` b ON a.`user_no`=b.`user_no`;


UPDATE order_info as aa INNER JOIN
(SELECT a.id,b.kefu_id FROM roncoo_education_course.`order_info` a JOIN roncoo_education_user.`user_ext` b ON a.`user_no`=b.`user_no`)bb on aa.id = bb.id set aa.kefu_id = bb.kefu_id

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原文地址：https://www.cnblogs.com/zhangrongfei/p/13039096.html