Question

如何在使用内部联接合并两个表时将列设置为PRIMARY KEY？（两个连接表中没有主键）请帮助

create table merge_aws AS
select aws.id,aws.date,aws.time,aws.pmer,aws.dd,aws.ff,aws.t,masterfile.station,masterfile.latitude,masterfile.longitude
from aws
inner join masterfile
on aws.id=masterfile.call_sign;

Answer 1

创建后使用alter table，如下例所示：

CREATE TABLE merge_aws AS select 
    aws.id,
    aws.date,
    aws.time,
    aws.pmer,
    aws.dd,
    aws.ff,
    aws.t,
    masterfile.station,
    masterfile.latitude,
    masterfile.longitude
from
    aws
        inner join
    masterfile ON aws.id = masterfile.call_sign;

ALTER TABLE merge_aws ADD COLUMN prim INT NOT NULL AUTO_INCREMENT , ADD PRIMARY KEY (prim) ;

谢谢

如何在使用内连接合并两个表时将列设置为PRIMARY KEY？（两个连接表中没有主键）

1 个答案: