SELECT t1.*,(SELECT "a" from t2 where t1.id=t2.aid) as t3
FROM
t1
以上为土办法，有高端方法请留言，谢谢
主从表关联查询合集
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Origin blog.csdn.net/liangyely/article/details/106118241
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SELECT t1.*,(SELECT "a" from t2 where t1.id=t2.aid) as t3
FROM
t1
以上为土办法，有高端方法请留言，谢谢