Question

我有一个名为people_temp_1的表，其中包含：

Name          Age          PersonID
John          25           1
Jane          32           2
Chris         47           3

另一个名为people_temp_2，其中包含由table1中的PersonID链接的其他信息：

ID          Profession          Location
1           Web Developer       Texas
2           Graphic Designer    North Carolina
3           Sales               California

我想创建一个名为people的新表，它“合并”来自两个表的数据。我现在如何做到这一点：

INSERT INTO people(name, age, profession, location)
SELECT people_temp_1.name AS name,
people_temp_2.age AS age,
(SELECT people_temp_2.profession FROM people_temp_2 WHERE people_temp_2.id = people_temp_1.personId) AS profession,
(SELECT people_temp_2.location FROM people_temp_2 WHERE people_temp_2.id = people_temp_1.personId) AS location
FROM people_temp_1

正如您所看到的，我在插入查询中使用了多个选择查询，以便通过personId获取相关的数据。当我应该以某种方式查询people_temp_2表并使用其所有列时，做多个选择查询似乎有点脏，但我无法弄清楚如何做到这一点。

有没有更好的方法来构造插入语句？

Answer 1

这是SQL的基础之一 - 使用join。在您的情况下，最好使用outer join，这样您就不会错过people_temp1中没有相应记录的people_temp2人：

insert into people(name, age, profession, location)
select
    p1.name,
    p1.age
    p2.profession,
    p2.location
from people_temp1 as p1
    left outer join people_temp2 as p2 on p2.id = p1.person_id

Answer 2

尝试使用如下的连接语法

INSERT INTO people(name, age, profession, location)
SELECT p1.namename,
p2.age,
p2.profession,
p2.location
FROM people_temp_1 p1
JOIN people_temp_2 p2 on p2.id = p1.personId

<强> More information about joins on mysql

Answer 3

使用JOIN。

INSERT INTO people(name, age, profession, location)
SELECT t1.name, t1.age, t2.profession, t2.location
FROM people_temp_1 t1
INNER JOIN people_temp_2 t2
ON t1.personid = t2.id

MySQL使用单独的SELECT查询从多个表插入表中

3 个答案: