mysql - 连接多个表并创建一个表

Question

我有 3 张桌子，名为 Advance、Transport 和 Medicine。我想加入这三个表，并为 emp_id 1 提供一个类似于最后一个表的表。是否可以使用 dql（doctrine）或 sql 在 sql 级别执行此操作？

Answer 1

CREATE TABLE NewTable
SELECT  Date, 
        Emp_ID,
        Amount As Advance, 
        NULL AS Transport,
        NULL AS Medicine
FROM    Advance
WHERE   Emp_ID = 1           -- remove this WHERE clause to include all emp_ID
UNION   ALL
SELECT  Date, 
        Emp_ID,
        NULL As Advance, 
        Amount AS Transport,
        NULL AS Medicine
FROM    Transport
WHERE   Emp_ID = 1           -- remove this WHERE clause to include all emp_ID
UNION   ALL
SELECT  Date, 
        Emp_ID,
        NULL As Advance, 
        NULL AS Transport,
        Amount AS Medicine
FROM    Medicine
WHERE   Emp_ID = 1           -- remove this WHERE clause to include all emp_ID

• 创建表...选择语法

您也可以VIEW在此创建一个，

CREATE VIEW EmployeeView
AS
SELECT  Date, 
        Emp_ID,
        Amount As Advance, 
        NULL AS Transport,
        NULL AS Medicine
FROM    Advance
WHERE   Emp_ID = 1           -- remove this WHERE clause to include all emp_ID
UNION   ALL
SELECT  Date, 
        Emp_ID,
        NULL As Advance, 
        Amount AS Transport,
        NULL AS Medicine
FROM    Transport
WHERE   Emp_ID = 1           -- remove this WHERE clause to include all emp_ID
UNION   ALL
SELECT  Date, 
        Emp_ID,
        NULL As Advance, 
        NULL AS Transport,
        Amount AS Medicine
FROM    Medicine
WHERE   Emp_ID = 1           -- remove this WHERE clause to include all emp_ID

• 创建视图语法