Question

对于学校项目，我编写了一个UFC数据库。我不知道如何写一些查询。一张桌子是关于战斗的

FIGHT:


 - Id_fight, integer, PK
 - Fighter1, integer, FK
 - Fighter2, integer, FK
 - Judge, integer, FK
 - WhichGala, integer, FK
 - HowManyRounds, integer
 - WhoWon, integer
 - HowWon, varchar2(50)

要知道获胜者，我创建了一个WhoWon列，可以为1（fighter1获胜）或2（fighter2获胜）。我想创建一些查询，但我不知道如何赢得比赛的胜利者。

查询： -重复显示所有战斗中的所有获胜者。

Answer 1

用例：

select distinct -- removes the duplicates
         case when WhoWon = 1 then Fighter1
              when WhoWon = 2 then Fighter2
              else 'Tied fight'
         end as Winners
from Mytable

您还可以算出他们赢得了多少：

select Winners, count(*) as fightswon
from
(
    select   case when WhoWon = 1 then Fighter1
                  when WhoWon = 2 then Fighter2
                  else 'Tied fight'
             end as Winners, ID_FIGHT
    from Mytable
)
-- Add any joins or where clauses here
group by Winners

SQL，根据其他列选择列

1 个答案: