问题描述 一条SQL的写法,菜鸟提问 式样要求从A表里取出所有项目,并且从B,C,D,E 4张表里取出和A表的nodeid相同的device这个字段. 我的想法是用t1 left join (select nodeid ,device from t2 union select nodeid ,device from t3 union select nodeid ,device from t4 union select nodeid ,device from t5) t6 on t1.nodeid