解決方案爲寫作查詢

Question

我有一個匹配的勝利隊和stadiumid作爲屬性， 我需要檢索贏得了所有比賽在同一體育場贏得勝利。

我想這一點，並且我得到額外的不利行：

select winningteamid 
from match 
group by winningteamid 
having count(winningteamid) in (
    select count(*) from match group by (winningteamid,stadiumid) 

Answer 1

你應該使用這樣的：

SELECT MAX(winningteamid) 
FROM (
    SELECT DISTINCT winningteamid, stadiumid 
    FROM match 
) 
GROUP BY stadiumid 
HAVING COUNT(*) = 1; 

Answer 2

試試這個，請（請寫出您所使用的RDBMS）：

with cte as (
    select winningteamid, stadiumid, count(stadiumid) over (partition by winningteamid) as count 
    from match 
    group by winningteamid, stadiumid 
) 
select * from cte where count = 1; 

Answer 3

我想這和使用HAVING來驗證只有一個不同的場館標識一樣簡單：

select winningteamid 
from match 
group by winningteamid 
having count(distinct stadiumid) = 1