MySQL可以用來(lái)創(chuàng)建二叉樹，并且可以通過(guò)遍歷這個(gè)二叉樹來(lái)實(shí)現(xiàn)各種不同的查詢等操作。下面是如何在MySQL中遍歷二叉樹：

--創(chuàng)建二叉樹
CREATE TABLE EmployeeTree (
EmployeeID INT PRIMARY KEY,
ManagerID INT,
EmployeeName VARCHAR(50),
FOREIGN KEY (ManagerID) REFERENCES EmployeeTree(EmployeeID)
);
--插入節(jié)點(diǎn)
INSERT INTO EmployeeTree (EmployeeID, ManagerID, EmployeeName) VALUES
(1, NULL, 'CEO'),
(2, 1, 'CFO'),
(3, 1, 'CTO'),
(4, 2, 'Finance Manager'),
(5, 2, 'HR Manager'),
(6, 3, 'Engineering Manager'),
(7, 6, 'Engineer1'),
(8, 6, 'Engineer2'),
(9, 6, 'Engineer3');
--通過(guò)遞歸遍歷二叉樹
DELIMITER //
CREATE PROCEDURE EmployeeTreeTraversal(IN startEmployeeID INT)
BEGIN
SELECT EmployeeID, EmployeeName
FROM EmployeeTree
WHERE EmployeeID = startEmployeeID
UNION ALL
SELECT EmployeeTree.EmployeeID, EmployeeTree.EmployeeName
FROM EmployeeTree
JOIN EmployeeTreeTraversal ON EmployeeTree.ManagerID = EmployeeTreeTraversal.EmployeeID
END //
--執(zhí)行遍歷
CALL EmployeeTreeTraversal(1);

以上代碼展示了如何創(chuàng)建一個(gè)員工樹（EmployeeTree）以及如何插入節(jié)點(diǎn)。然后我們使用遞歸來(lái)遍歷整個(gè)樹。這里我們創(chuàng)建了一個(gè)名為EmployeeTreeTraversal的存儲(chǔ)過(guò)程，通過(guò)傳入起始EmployeeID來(lái)遍歷整個(gè)樹。

在這個(gè)存儲(chǔ)過(guò)程內(nèi)，我們使用了MySQL的遞歸，通過(guò)聯(lián)接EmployeeTree表和EmployeeTreeTraversal存儲(chǔ)過(guò)程的結(jié)果，來(lái)遍歷整個(gè)二叉樹。這個(gè)存儲(chǔ)過(guò)程將會(huì)返回從起始節(jié)點(diǎn)開始的所有下級(jí)員工的信息。