有2张表 每张表大概1500W的数据
表一字段:
id pid name....
表二字段:
id pid age....
现在要将表的数据合并了
id pid name age...
怎么样实现比较好
回复内容:
有2张表 每张表大概1500W的数据
表一字段:
id pid name....
表二字段:
id pid age....
现在要将表的数据合并了
id pid name age...
怎么样实现比较好
假设age这张表的pid是这样的:
<code>1 2 3 4 5 6 7 ... </code>
然后name这张表的pid是这样的:
<code>1 3 5 6 ... </code>
即name.pid (foreign key references on age.pid)
我们可以尝试下面这条SQL语句:
<code>SELECT * FROM name RIGHT OUTER JOIN age ON name.pid = age.pid ; </code>
写sql合并就行了, 不知道 两个表的 id 和pid相同不
还有合并的时候是在线上?还是线下?需要保证数据库还能对外提供服务么
如果只保留一个id,以保留t1表为例
insert into t3(id,pid,name,age) select t1.id,t1.pid,t1.name,t2.age from t1,t2 where t1.pid = t2.pid;
如果两个id都要保留
insert into t3(id1,id2,pid,name,age) select t1.id,t2.id,t1.pid,t1.name,t2.age from t1,t2 where t1.pid = t2.pid;
<code>insert into t3(pid,name,age) select t1.pid,t1.name,t2.age from t1 left join t2 on t1.pid = t2.pid </code>

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