加入多个表并创建一个表

Question

我有3张名为Advance，Transport and Medicine的表格。我想加入这三个表，并为emp_id 1创建一个像最后一个表的表。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

• CREATE TABLE...SELECT Syntax

您还可以在此处创建VIEW

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

• CREATE VIEW Syntax