Question

CREATE TABLE Coins (Badge VARCHAr(10), Cointype INT,  Number INT);

INSERT INTO Coins (Badge,Cointype, Number) VALUES
('' , 1, 1),
('' , 5, 2),
('' , 20, 3),
('' , 1, 4),
('' , 5, 5),
('' , 5, 6),
('' , 5, 7),
('RESET', 0 , 0),
('' , 1, 8),
('' , 10, 9),
('RESET', 0 , 0),
('' , 5, 10),
('' , 20, 11);

嗨，有了这张表，我希望在第一行（'RESET'，0,0）之上有以下总和

select 
SUM(case when Cointype=1 Then Number else 0 END) as SUM1,
SUM(case when Cointype=5 Then Number else 0 END) as SUM5,
SUM(case when Cointype=20 Then Number else 0 END) as SUM20
from Coins

结果必须是这样的：

SUM1    SUM5    SUM20
5       20      3

这可能在MySql中吗？

在实际情况中，还有一个ID和时间戳字段。最高记录是具有最高ID和时间戳的最新记录。因此，最新的记录必须汇总到RESET行。（如果我们需要订购，可以使用ID或时间戳字段）

然后表格是这样的：

CREATE TABLE Coins (ID INT, Badge VARCHAr(10), Cointype INT,  Number INT);

INSERT INTO Coins (ID, Badge,Cointype, Number) VALUES
(13,'' , 1, 1),
(12,'' , 5, 2),
(11,'' , 20, 3),
(10,'' , 1, 4),
(9,'' , 5, 5),
(8,'' , 5, 6),
(7,'' , 5, 7),
(6,'RESET', 0 , 0),
(5,'' , 1, 8),
(4,'' , 10, 9),
(3,'RESET', 0 , 0),
(2,'' , 5, 10),
(1,'' , 20, 11);

Answer 1

如果您有自动数字列：

<强> SQL DEMO

select 
    SUM(case when Cointype=1 Then Number else 0 END) as SUM1,
    SUM(case when Cointype=5 Then Number else 0 END) as SUM5,
    SUM(case when Cointype=20 Then Number else 0 END) as SUM20
from Coins 
WHERE ID < ( SELECT MIN(ID)
             FROM Coins
             WHERE Badge = 'RESET' )

<强>输出

| SUM1 | SUM5 | SUM20 |
|------|------|-------|
|    5 |   20 |     3 |

修改

更改样本后，看起来行的顺序相反。然后，您需要MAX()而不是MIN()

select SUM(case when Cointype=1 Then Number else 0 END) as SUM1, SUM(case when Cointype=5 Then Number else 0 END) as SUM5, SUM(case when Cointype=20 Then Number else 0 END) as SUM20 from Coins WHERE ID > ( SELECT MAX(ID) FROM Coins WHERE Badge = 'RESET' )

选择sum直到找到特定的行

1 个答案: