Question

我有3张桌子。其中2个是相同的（相同的列，不同的数据），第三个有关于其他的一些信息数据2.数据库看起来像这样：

表1：

+--------------+
|  ID | Name   |
+--------------+
| 1  | Table 2 |
| 2  | Table 3 |
+--------------+

表2：

+-------------------------------+
| Name | Temperature | Pressure |
+-------------------------------+
| Table 2 |    22    | 1013     |
+-------------------------------+

表3：

+-------------------------------+
| Name | Temperature | Pressure |
+-------------------------------+
| Table 3 |    20    | 1009     |
+-------------------------------+

我正在尝试将所有内容加入到一个表中，它应该如下所示：

+-------------------------------+
| Name | Temperature | Pressure |
+-------------------------------+
| Table 2 |    22    | 1013     |
| Table 3 |    20    | 1009     |
+-------------------------------+

知道sql查询应该如何？

由于

Answer 1

尝试结合：

SELECT table1.name, temperature, pressure 
FROM table1 inner join table2 ON
table1.name = table2.name
UNION
SELECT table1.name, temperature, pressure 
FROM table1 inner join table3 ON
table1.name = table3.name

编辑：您可以从这些结果中进行另一个选择，然后您可以限制，分组或订购：

SELECT * FROM
(
    SELECT table1.name, temperature, pressure 
    FROM table1 inner join table2 ON
    table1.name = table2.name
    UNION
    SELECT table1.name, temperature, pressure 
    FROM table1 inner join table3 ON
    table1.name = table3.name
) as JoinedTable
LIMIT 0, 1

编辑2：要从每个表（表2和表3）只有一行，您可以为每个查询使用limit / group by / order by（假设您有列日期）：

SELECT table1.name, temperature, pressure 
FROM table1 inner join table2 ON
table1.name = table2.name
ORDER BY date DESC
LIMIT 0, 1
UNION
SELECT table1.name, temperature, pressure 
FROM table1 inner join table3 ON
table1.name = table3.name
ORDER BY date DESC
LIMIT 0, 1

Answer 2

您可以使用UNION声明：

(
    SELECT Name, Temperature, Pressure
    FROM Table1 INNER JOIN Table2 ON Table1.Name = Table2.Name
)
UNION
(
    SELECT Name, Temperature, Pressure
    FROM Table1 INNER JOIN Table3 ON Table1.Name = Table3.Name
)

Mysql JOIN（多个）表

2 个答案: