mysql - Oracle MYSQL 执行计划

Question

Oracle 在上面和下面执行查询的方式有区别吗？

第一个查询：

SELECT 
D.DName AS Department,
E3.Name AS Manager,
P.pTitle AS Project,
E2.Name AS Supervisor,
E2.Name AS Employee,
W.Hours
FROM
Department D,
Employee E1,
Employee E2,
workson W,
project P,
Employee E3
WHERE
D.Dnumber = P.Dnumber
    AND P.Pnumber = W.Pnumber
    AND W.Enumber = E1.Enumber
    AND E1.Supervisor = E2.ENumber
    AND D.Manager = E3.ENumber
ORDER BY P.pTitle;

第二个查询：

SELECT 
D.DName AS Department,
E3.Name AS Manager,
P.pTitle AS Project,
E2.Name AS Supervisor,
E2.Name AS Employee,
W.Hours
FROM
Department D,
Employee E1,
Employee E2,
workson W,
project P,
Employee E3
WHERE
D.Dnumber = P.Dnumber
    AND P.Pnumber = W.Pnumber
    AND W.Enumber = E1.Enumber
    AND E1.Supervisor = E2.ENumber
    AND D.Manager = E3.ENumber
 ORDER BY E3.Name;

我的sql中以上两个代码的执行计划有什么不同？它会有所不同还是会保持不变？上述代码的执行计划将如何？它们彼此有什么不同吗？

标签： mysql