库1 gxjob
库2 funshixi
SELECT a.`company_id`,b.`companyname` FROM `gxjob`.`qj_activity_thousands_of_schools` AS a LEFT JOIN `funshixi`.`qj_company` AS b ON a.company_id = b.companyid;
MySQL跨库查询例子
原文：https://www.cnblogs.com/clubs/p/9255281.html
