连接两个查询时出现问题 Oracle SQL

Question

我对这样的员工有一个 table：

ENAME     JOB 
Jack      Clerk
Adam      Manager
Raphael   President

我的想法是获取具有最大长度和最小长度的名称（每个 1 个），如果长度相同，则取按字母顺序排在第一位的名称（例如在Jack 和 Adam，都是 4 个字符，需要 Adam):

ENAME      LENGTH
Adam         4
Raphael      7

我找不到在一个唯一查询中执行此操作的方法，因此我尝试加入两个查询，但它一直给我错误 ('ORA-00933: SQL command not properly ended')，我不知道为什么：

SELECT ENAME, LENGTH(ENAME) FROM EMP
GROUP BY ENAME
HAVING LENGTH(ENAME) = (SELECT MAX(LENGTH(ENAME)) FROM emp) 
ORDER BY ENAME
FETCH FIRST 1 ROW ONLY
union all
SELECT ENAME, LENGTH(ENAME) FROM EMP
GROUP BY ENAME
HAVING LENGTH(ENAME) = (SELECT MIN(LENGTH(ENAME)) FROM emp) 
ORDER BY ENAME
FETCH FIRST 1 ROW ONLY;

Answer 1

一种方法使用聚合和 union all:

select min(name) keep (dense_rank first order by len(name) asc), min(len(name))
from emp
union all
select min(name) keep (dense_rank first order by len(name) desc, max(len(name))
from emp;

keep 语法是 Oracle 具有“第一个”聚合函数的相当冗长的方式。

Answer 2

SELECT ENAME, LENGTH(ENAME) FROM EMP
GROUP BY ENAME
HAVING LENGTH(ENAME) = (SELECT MAX(LENGTH(ENAME)) FROM emp) 
--ORDER BY 1
--FETCH FIRST 1 ROW ONLY
union 
SELECT ENAME, LENGTH(ENAME) FROM EMP
GROUP BY ENAME
HAVING LENGTH(ENAME) = (SELECT MIN(LENGTH(ENAME)) FROM emp) 
ORDER BY 1
FETCH FIRST 1 ROW ONLY;

连接两个查询时出现问题 Oracle SQL

Trouble when joining two queries Oracle SQL

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