如何在SQL中正确使用临时表

Question

我试图使用临时表来简化我的查询，但我得到了一条错误消息。下面是我的问题：

SELECT E.ID, E.name
INTO #TmpEmplyee
FROM Employee E, Outsourcing O, Student S
WHERE E.ID NOT IN (SELECT ID FROM Student UNION SELECT ID FROM Outsourcing)

SELECT R.name, I.startDate, T.name
FROM Role R, Inn I, #TmpEmplyee T
WHERE I.name = R.name AND I.ID = T.id

错误是：

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM Employee E, Outsourcing O, Student S WHERE E.ID NOT IN (SELECT ID FROM Stud' at line 3

谢谢你的帮助！

Answer 1

要从select创建临时表，应使用以下语法

CREATE TEMPORARY TABLE mytemptable 
SELECT Field1, Field2 
FROM mytable;

Answer 2

在mysql中，您需要在查询之前创建临时表。此外，您不需要在表单中选择外包O，学生S，因为您不是从它们中进行选择：

INSERT INTO #TmpEmplyee
SELECT E.ID, E.name
FROM Employee E
WHERE E.ID NOT IN (SELECT ID FROM Student UNION SELECT ID FROM Outsourcing)

Answer 3

试一试，

SELECT R.name, I.startDate, T.name
FROM    Role R 
        INNER JOIN Inn I
            ON I.name = R.name
        INNER JOIN
        (
            SELECT E.ID, E.name
            -- remember that the join below produces CROSS JOIN
            FROM Employee E, Outsourcing O, Student S
            WHERE E.ID NOT IN ( SELECT ID FROM Student 
                                UNION 
                                SELECT ID FROM Outsourcing)
        ) T ON I.ID = T.id