TSQL, help with small query about user's age

问题

I have a table with registered users, in which i save year as varchar values simply because i take just an year. I want to create pie chart with ages to show which users are more likely to register.

Query below gives me count of user ages which appear more than 5 times in Table to avoid small results. While these small results, below "having ount(userID)>5" i want to appear as others. What should i add to this query or possibly to re-design it. I can create silly solutions like to take all years that appear in initial query and then select all besides those year but there must be better and more creative way of writing this query.

So result will be something like that 1 10 1990 2 4 1980 3 10 others

select count(userID) ageCount,userBirthYear from Users
group by userBirthYear
having count(userID)>5
order by count(userID) desc

thanks

回答1:

Here's one way (assuming SQL2005 or later).

With Ages As
(
select count(userID) ageCount,userBirthYear 
from Users
group by userBirthYear
)

SELECT ageCount,userBirthYear FROM Ages WHERE ageCount>5
UNION ALL
SELECT sum(ageCount) ,'others' As userBirthYear FROM Ages WHERE ageCount<=5

回答2:

Here's a regrouping solution (union-less) to avoid repeated IO.

The basic idea is you want every record to contribute to the result, so there should be no WHERE or HAVING clauses.

SELECT
  SUM(sub.ageCount) as ageCount,
  sub.userBirthYear
FROM
(
  SELECT Count(userId) ageCount,
    CASE WHEN COUNT(userID) > 5)
         THEN userBirthYear
         ELSE 'Other'
    END as userBirthYear
  FROM Users
  GROUP BY userBirthYear
) as sub
GROUP BY sub.userBirthYear

回答3:

select  count(userID) ageCount,userBirthYear from Users 
group   by userBirthYear 
having  count(userID)>5 
union
SELECT  SUM(agecount), 'Others' 
FROM    (select count(userID) ageCount,'Others' userBirthYear from Users 
     group  by userBirthYear 
     having count(userID)<5)TMP 
order by    count(userID) desc

来源：https://stackoverflow.com/questions/3101653/tsql-help-with-small-query-about-users-age

标签

sql

sql-server

tsql