从MySQL获取分层数据

时间:2013-05-21 20:21:31

标签: mysql

我有两张桌子。团队和球员。我想要做的是创建一个查询,告诉我一些关于最大团队薪水的统计数据。具体来说,我想要计算有多少玩家少于5K。 5K到10K之间的数量是多少....以5K的增量增加到最大玩家。

这是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'); 

鉴于此数据:道奇队是最大的球队(ID = 4) 我们希望输出:

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

如果这段代码看起来很熟悉,那是因为它是我在这里发布的先前问题的演变。请不要打倒我!

2 个答案:

答案 0 :(得分:3)

这是我对此的尝试。它使用连接来满足条件:

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)

请注意对范围使用单独的查询,以确保获得计数为0的行。

答案 1 :(得分:1)

此代码几乎可以执行您想要的操作

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

它返回范围的低边框和条目数

0        1
5000     2
15000    1

请注意,它不会返回空范围。