sql - 在一个查询中，获取姓氏长度、名字长度和按长度分组 - 三列

Question

我是一个菜鸟......并且正在处理家庭作业问题。

有一个包含姓氏、名字的成员表。我想编写一个查询，通过字符串长度聚合 last_name、first_name 的长度。

输出将包含三列 - name_length、count_of_last_names、count_of_first_names。

两个单独的查询：

`SELECT LENGTH(last_name) AS "LnameLen", COUNT(LENGTH(last_name)) AS "CntLnameLen"
FROM members
GROUP BY LENGTH(last_name)
ORDER BY "LnameLen" DESC;

SELECT LENGTH(first_name) AS "FnameLen", COUNT(LENGTH(first_name)) AS "CntFnameLen"
FROM members
GROUP BY LENGTH(first_name)
ORDER BY "FnameLen";`

但是我想编写一个查询来输出上述两个查询所做的事情，因此输出将是三列：Length_of_Name、CntLnameLen、CntFnameLen。

建议？谢谢！

Answer 1

我理解这个问题的方式，像这样的东西可能就是你正在寻找的东西。

select length(first_name), 
       length(last_name),
       count(*)
from members
group by length(first_name), 
         length(last_name);