合并为单个查询

【问题标题】：Merge as Single Query合并为单个查询
【发布时间】：2017-03-24 10:00:41
【问题描述】：

查询 STATION 中两个城市的 CITY 名称最短和最长，以及它们各自的长度（即：名称中的字符数）。如果有多个最小或最大的城市，请选择按字母顺序排列在前的城市。

SELECT CITY,CHAR_LENGTH(CITY) AS CHARLENGTH 
FROM STATION 
ORDER BY CHARLENGTH ASC 
LIMIT 1;

SELECT CITY,CHAR_LENGTH(CITY) AS CHARLENGTH 
FROM STATION 
ORDER BY CHARLENGTH DESC 
LIMIT 1;

【问题讨论】：

标签： mysql sql

【解决方案1】：

这样的？

##DROP TABLE STATION;
CREATE TABLE STATION (CITY VARCHAR(100));
INSERT INTO STATION VALUES ('aaaaaaa');
INSERT INTO STATION VALUES ('bbbbbbb');
INSERT INTO STATION VALUES ('cccc');
INSERT INTO STATION VALUES ('dd');
SELECT * 
FROM 
(SELECT CITY,CHAR_LENGTH(CITY) AS CHARLENGTH FROM STATION ORDER BY CHARLENGTH ASC, CITY LIMIT 1) A
UNION ALL
SELECT * FROM 
(SELECT CITY,CHAR_LENGTH(CITY) AS CHARLENGTH FROM STATION ORDER BY CHARLENGTH DESC, CITY  LIMIT 1) B

输出：

    CITY    CHARLENGTH
1   dd  2
2   aaaaaaa 7

【讨论】：