从MySQL获取分层数据

我有两个表。球队和球员。我想要做的是创建一个查询，告诉我关于最大团队薪水的一些统计数据。具体而言，我要计算有多少玩家少于5K。有多少人在5K和10K之间......以5K为增量给最高玩家。从MySQL获取分层数据

这里是SQL：

CREATE TABLE `formsfiles`.`Teams` (
    `ID` INT NOT NULL AUTO_INCREMENT , 
    `Name` VARCHAR(45) NULL , 
    PRIMARY KEY (`ID`)); 


INSERT INTO `Teams` (`Name`) VALUES ('Sharks'); 
INSERT INTO `Teams` (`Name`) VALUES ('Jets'); 
INSERT INTO `Teams` (`Name`) VALUES ('Fish'); 
INSERT INTO `Teams` (`Name`) VALUES ('Dodgers'); 


CREATE TABLE `Players` (
    `ID` INT NOT NULL AUTO_INCREMENT , 
    `Name` VARCHAR(45) NULL , 
    `Team_ID` INT NULL , 
    `Salary` INT NUll , 
    PRIMARY KEY (`ID`)); 

INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Jim', '1', '4800'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Tom', '1', '12000'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Harry', '2', '1230'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Dave', '2', '19870'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Tim', '3', '1540'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Trey', '4','7340'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Jay', '4', '4800'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Steve', '4','6610'); 
INSERT INTO `Players` (`Name`, `Team_ID`, salary) VALUES ('Chris', '4','17754');

鉴于这样的数据：道奇队是最大的球队（ID = 4）我们想的输出：

0-5000  1 
5000-10000 2 
10000-15000 0 
15000-20000 1

如果这个代码看起来我很熟悉它是因为它是我在这里发布的一个先前问题的一个进化问题。请不要把我打倒！

来源

2013-05-21 JVMX

你可以选择它们之间的简单条件，并将它们联合起来 – rcpayan

计数该代码会做什么几乎你行要

SELECT 5000 * FLOOR(Salary/5000), count(*) 
FROM Players 
WHERE Team_ID = 4 
GROUP BY FLOOR(Salary/5000)

它返回的范围内的低边界和条目数

0  1 
5000  2 
15000 1

请注意，它不会返回空范围。

来源

2013-05-21 20:41:08 zavg

这是我的尝试。它采用加入到满足条件：

select sr.range, 
     SUM(case when p.salary >= sr.low and p.salary < sr.high then 1 else 0 end)   
from Players p join 
    (select t.id 
     from Players p join 
      Teams t 
      on p.team_id = t.id 
     group by t.team_id 
     order by SUM(p.salary) desc 
     limit 1 
    ) team 
    on p.team_id = team.id cross join 
    (select '0-5000' as range, 0 as low, 5000 as high union all 
     select '5000-10000', 5000, 10000 union all 
     select '10000-15000', 10000, 15000 union all 
     select '15000-20000', 15000, 20000 
    ) sr 
group by sr.range 
order by min(sr.low)

注意使用的范围内单独查询，以确保你得到的0

来源

2013-05-21 20:39:19

从MySQL获取分层数据

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