Question

好的，我有多个表，我试图基本上形成一个SQL字符串。表格示例：

表1

CardID    CardName    SetID    Rarity
1         Card #1     1        1
2         Card #2     1        2
3         Card #3     1        2
4         Card #4     2        2

表2

SetID     SetName     BID
1         Set #1      1
2         Set #2      2

表3

BID       BName
1         BName #1
2         BName #2

我想要的是一个SQL字符串，它可以计算一组的卡片，并显示该表中每张卡片的稀有性。我想要一个类似于的输出： SetID，SetName，BName，TotalCards，Rarity 1的总和，Rarity 2的总和

因此输出类似于返回列：

1, Set #1, BName #1, 3, 1, 2
2, Set #2, BName #2, 1, 0, 1

Answer 1

SELECT 
  c.SetID
  , s.SetName
  , b.BName 
  , count(*) as TotalCards
  , sum(if(c.rarity = 1,1,0) as Total_of_Rarity_1
  , sum(if(c.rarity = 2,1,0) as Total_of_Rarity_2
FROM card c
INNER JOIN `set` s ON (s.SetID = c.SetID)
INNER JOIN b on (b.BID = s.BID)
GROUP BY c.SetID

链接：http://dev.mysql.com/doc/refman/5.5/en/join.html

使用MySQL拉出多个表

1 个答案: