小美是一所中學的信息科技老師，她有一張?seat?座位表，平時用來儲存學生名字和與他們相對應的座位 id。

其中縱列的?id?是連續遞增的

小美想改變相鄰倆學生的座位。

你能不能幫她寫一個 SQL query?來輸出小美想要的結果呢？

示例：

+---------+---------+

| id | student |

+---------+---------+

| 1 | Abbot |

| 2 | Doris |

| 3 | Emerson |

| 4 | Green |

| 5 | Jeames |

+---------+---------+

假如數據輸入的是上表，則輸出結果如下：

+---------+---------+

| id | student |

+---------+---------+

| 1 | Doris |

| 2 | Abbot |

| 3 | Green |

| 4 | Emerson |

| 5 | Jeames |

+---------+---------+

注意：

如果學生人數是奇數，則不需要改變最后一個同學的座位。

# Write your MySQL query statement below

SELECT * FROM(

SELECT id-1 AS id,student FROM seat WHERE id%2=0

UNION

SELECT id+1 AS id,student FROM seat WHERE id%2=1 AND (id+1) <= (SELECT COUNT(*) FROM seat)

UNION

SELECT id AS id,student FROM seat WHERE id%2=1 AND (id+1) > (SELECT COUNT(*) FROM seat)

) AS T1

ORDER BY id ASC

標簽：數據庫,seat,力扣,student,query,座位,id,SELECT

來源： https://www.cnblogs.com/JAYPARK/p/10351175.html