在SQL

Question

使用聚合函數max我有以下查詢

select 
    sub.W 
from 
    (select 
     W, count(W) as N 
    from L 
    group by W) sub 
where 
    sub.N >= max(sub.N) 

，我得到這個錯誤：

Error code 1111, SQL state HY000: Invalid use of group function
Line 1, column 1

有什麼不對？

Answer 1

嘗試：

select sub.W  
from 
(
     select W, count(W) as N 
     from L 
     group by W 
) sub  
where sub.N >= (select max(N) 
       from (
         select W, count(W) as N 
         from L 
         group by W 
        ) sub2) 

Answer 2

你有沒有嘗試過這樣的：

select sub.W 
from 
(
     select W, count(W) as N 
     from L 
     group by W 
) sub 
where n >= (select max(N) 
      from 
      (
       select count(W) as N 
       from L 
       group by W 
      ) x) 

見SQL Fiddle with Demo