Question

我无法弄清楚如何按分组类别对数据进行排名。

例如，下面是来自R的mtcars数据集的代码。在oracle中，我想

按某种方式分组，说'＆＃39; gear＆＃39;，对该组中每辆车的MPG取平均值，并显示每组的平均mpg等级

select gear, avg(MPG), rank() over (partition by gear order by avg(MPG))
FROM mtcars
group by hp

此外，如果有人能告诉我如何按多个群组或＆＃39;小组进行分组。我会很感激。下面的代码

CREATE TABLE MTCARS 
("MPG" NUMBER(5,2), 
"CYL" NUMBER, 
"DISP" NUMBER(5,2), 
"HP" NUMBER, 
"DRAT" NUMBER(5,2), 
"WT" NUMBER(5,2), 
"QSEC" NUMBER(5,2), 
"VS" NUMBER, 
"AM" NUMBER, 
"GEAR" NUMBER, 
"CARB" NUMBER
) 



 INSERT INTO mtcars  VALUES ('21','6','160','110','3.9','2.62','16.46','0','1','4','4');
 INSERT INTO mtcars  VALUES ('21','6','160','110','3.9','2.875','17.02','0','1','4','4');
INSERT INTO mtcars   VALUES ('22.8','4','108','93','3.85','2.32','18.61','1','1','4','1');
 INSERT INTO mtcars   VALUES ('21.4','6','258','110','3.08','3.215','19.44','1','0','3','1');
  INSERT INTO mtcars   VALUES ('18.7','8','360','175','3.15','3.44','17.02','0','0','3','2');
  INSERT INTO mtcars   VALUES ('18.1','6','225','105','2.76','3.46','20.22','1','0','3','1');
  INSERT INTO mtcars   VALUES  ('14.3','8','360','245','3.21','3.57','15.84','0','0','3','4');
  INSERT INTO mtcars   VALUES ('24.4','4','146.7','62','3.69','3.19','20','1','0','4','2');
  INSERT INTO mtcars   VALUES ('22.8','4','140.8','95','3.92','3.15','22.9','1','0','4','2');
  INSERT INTO mtcars   VALUES ('19.2','6','167.6','123','3.92','3.44','18.3','1','0','4','4');

  INSERT INTO mtcars   VALUES ('17.8','6','167.6','123','3.92','3.44','18.9','1','0','4','4');

  INSERT INTO mtcars   VALUES ('16.4','8','275.8','180','3.07','4.07','17.4','0','0','3','3');

  INSERT INTO mtcars   VALUES ('17.3','8','275.8','180','3.07','3.73','17.6','0','0','3','3');

  INSERT INTO mtcars   VALUES ('15.2','8','275.8','180','3.07','3.78','18','0','0','3','3');

  INSERT INTO mtcars   VALUES ('10.4','8','472','205','2.93','5.25','17.98','0','0','3','4');

  INSERT INTO mtcars   VALUES ('10.4','8','460','215','3','5.424','17.82','0','0','3','4');

   INSERT INTO mtcars   VALUES ('14.7','8','440','230','3.23','5.345','17.42','0','0','3','4');

  INSERT INTO mtcars   VALUES ('32.4','4','78.7','66','4.08','2.2','19.47','1','1','4','1');

  INSERT INTO mtcars   VALUES ('30.4','4','75.7','52','4.93','1.615','18.52','1','1','4','2');

  INSERT INTO mtcars   VALUES ('33.9','4','71.1','65','4.22','1.835','19.9','1','1','4','1');

  INSERT INTO mtcars   VALUES ('21.5','4','120.1','97','3.7','2.465','20.01','1','0','3','1');

  INSERT INTO mtcars   VALUES ('15.5','8','318','150','2.76','3.52','16.87','0','0','3','2');
  INSERT INTO mtcars   VALUES ('15.2','8','304','150','3.15','3.435','17.3','0','0','3','2');
  INSERT INTO mtcars   VALUES ('13.3','8','350','245','3.73','3.84','15.41','0','0','3','4');

  INSERT INTO mtcars   VALUES ('19.2','8','400','175','3.08','3.845','17.05','0','0','3','2');

  INSERT INTO mtcars   VALUES ('27.3','4','79','66','4.08','1.935','18.9','1','1','4','1');

   INSERT INTO mtcars   VALUES ('26','4','120.3','91','4.43','2.14','16.7','0','1','5','2');

  INSERT INTO mtcars   VALUES ('30.4','4','95.1','113','3.77','1.513','16.9','1','1','5','2');
  INSERT INTO mtcars   VALUES ('15.8','8','351','264','4.22','3.17','14.5','0','1','5','4');
  INSERT INTO mtcars   VALUES ('19.7','6','145','175','3.62','2.77','15.5','0','1','5','6');
  INSERT INTO mtcars   VALUES ('15','8','301','335','3.54','3.57','14.6','0','1','5','8');
  INSERT INTO mtcars   VALUES ('21.4','4','121','109','4.11','2.78','18.6','1','1','4','2');

Answer 1

你可以这样做

<强> SQL Fiddle Demo

SELECT gear, 
    AVG(mpg) AS avgMpg,
    RANK() OVER(ORDER BY AVG(mpg) DESC) as Rank
FROM mtcars
GROUP BY gear

在Oracle sql中按分组类别排名

1 个答案: