我必须为数据库编写查询。查询在下面。
/* Query 9 – Most Valuable Players
"Who has received at least 2 MVP awards?"
Produce a query to display the full name and number of MVP awards of any players who have been awarded the MVP in at least 2 races.
Make sure that races where no MVP was awarded are not included in the results, and order your results by the number of MVP awards in descending order.
Using your race view in this query is recommended.
Hint: Use HAVING to limit the results to players with an MVP count of at least 2.
我已经尝试使用此代码：
CREATE VIEW playerView1
AS
select
player.id, player.firstName + ' ' + player.surname AS 'Full Name', race.mvp
from
player
JOIN
race ON player.team = race.team
GO
SELECT playerView1.[Full Name]
From playerView1
GROUP BY [Full Name]
HAVING (playerView1.mvp) >1
，也尝试了
SELECT
player.firstName + ' ' + player.surname AS 'Full_name', raceView.mvp AS 'MVP Number',
raceView.mvp_name AS 'MVP Name'
FROM
raceView
JOIN
player ON raceView.mvp_name = player.firstName
WHERE
raceView.mvp > 1
，没有运气。关于我出错的地方有什么想法吗？可能是修复？
我使用第一个查询遇到的错误之一是
msg 8121，级别16，状态1，第4行
" PlayerView1.mvp"列在HADHE子句中无效，因为它不包含在汇总函数中，或者由子句中的组中包含。
下面是我的整个数据库脚本，在能够进行查询之前包括创建，填充和查看，从而导致我的问题。
IF DB_ID ('Assignment2') IS NOT NULL
BEGIN
DROP DATABASE Assignment2;
END
/* Now create new database*/
CREATE DATABASE Assignment2;
GO
/* Make system use new database */
USE Assignment2;
/* Begin Creating tables */
/** Create Course Table **/
PRINT 'Creating table course.';
CREATE TABLE course (
id INT IDENTITY, -- [CourseID] [int] IDENTITY(1,1) NOT NULL,
name VARCHAR(50), -- [CourseName] [varchar](50) NULL,
passingScore NUMERIC(18,0), -- [PassingScore] [numeric](18, 0) NOT NULL,
CONSTRAINT course_pk PRIMARY KEY (id),
CONSTRAINT passingScore CHECK (passingScore BETWEEN 0 AND 100)
);
/** Create RaceType Table**/
PRINT 'Creating table Race Type.'
CREATE TABLE raceType (
id INT IDENTITY, -- [RaceTypeID] [int] IDENTITY(1,1) NOT NULL,
name VARCHAR(25) NOT NULL, -- [RaceTypeName] [varchar](25) NOT NULL,
CONSTRAINT raceType_pk PRIMARY KEY (id),
CONSTRAINT raceType_unique UNIQUE (name)
);
/** Create 'Teams' Table */
PRINT ' Creating table called Teams'
CREATE TABLE team (
id INT IDENTITY, -- [TeamID] [int] IDENTITY (1,1) NOT NULL,
name VARCHAR(25) NOT NULL, -- [TeamName] [varchar] (25) NOT NULL,
biography TEXT, -- [Biography] [text] NULL,
hyperlink VARCHAR(max), -- [Hyperlink] [varchar] (max) NULL,
CONSTRAINT team_pk PRIMARY KEY (id),
CONSTRAINT team_unique UNIQUE (name)
);
/** Create "Players" Table**/
PRINT ' Creating table called Players'
CREATE TABLE player (
id INT IDENTITY, -- [PlayerID] [int] IDENTITY(1,1) NOT NULL,
firstName VARCHAR(50) NOT NULL, -- [FirstName] [varchar](50) NOT NULL,
surname VARCHAR(50) NOT NULL, -- [Surname] [varchar](50) NOT NULL,
coach INT, -- fk1 [CoachID] [int] NULL,
team INT, -- fk2 [TeamID] [int] NULL,
CONSTRAINT player_pk PRIMARY KEY (id),
CONSTRAINT player_fk1 FOREIGN KEY (team) REFERENCES team (id),
CONSTRAINT player_fk2 FOREIGN KEY (coach) REFERENCES player (id)
);
/** Create "Races" Table **/
PRINT ' Creating table called Races'
CREATE TABLE race (
id INT IDENTITY, -- [RaceID] [int] IDENTITY(1,1) NOT NULL,
dateOfRace DATETIME NOT NULL, -- [DateOfRace] [datetime] NOT NULL,
raceType INT NOT NULL, -- [RaceTypeID] [int] NOT NULL,
course INT NOT NULL, -- [CourseID] [int] NOT NULL,
team INT NOT NULL, -- [TeamID] [int] NOT NULL,
observer INT NOT NULL, -- [ObserverID] [int] NOT NULL,
mvp INT NULL, -- [MvpPlayerID] [int] NULL,
finalScore INT NOT NULL, -- [FinalScore] [int] NOT NULL,
pointsPenalised INT NOT NULL, -- [PointsPenalised] [int] NOT NULL,
CONSTRAINT race_pk PRIMARY KEY (id),
CONSTRAINT race_fk1 FOREIGN KEY (raceType) REFERENCES raceType(id),
CONSTRAINT race_fk2 FOREIGN KEY (course) REFERENCES course(id),
CONSTRAINT race_fk3 FOREIGN KEY (team) REFERENCES team(id),
CONSTRAINT race_fk4 FOREIGN KEY (observer) REFERENCES player(id),
CONSTRAINT race_fk5 FOREIGN KEY (mvp) REFERENCES player(id)
);
GO
/** End*/
填充脚本
/** Begin Populating "Course" table*/
PRINT 'Populating Course Table'
INSERT INTO course (name,passingScore)
VALUES ('Easy Course','80');
INSERT INTO course (name,passingScore)
VALUES ('Medium Course','70');
INSERT INTO course (name,passingScore)
VALUES ('Hard Course','60');
/** Begin Populating "RaceType" Table */
PRINT 'Populating RaceType Table '
INSERT INTO raceType (name)
VALUES ('Ranked')
INSERT INTO raceType (name)
VALUES ('Practise')
/** Begin Populating "Teams" Table */
PRINT ' Populating Teams Table'
INSERT INTO team (name)
VALUES ('Team BMW');
INSERT INTO team (name)
VALUES ('Team Porsche');
INSERT INTO team (name)
VALUES ('Team Mercedez');
INSERT INTO team (name)
VALUES ('Team AMartin');
INSERT INTO team (name)
VALUES ('Team Audi');
INSERT INTO player (firstName, surname)
VALUES ('hoger','amedi');
INSERT INTO player (firstName, surname, coach, team)
VALUES (' Lloyd', 'Banks', 1, 1);
INSERT INTO player (firstName, surname)
VALUES ('Silav', 'Govand');
INSERT INTO player (firstName, surname, coach, team)
VALUES ('hell', 'razor', 2, 2);
INSERT INTO player (firstName, surname, coach, team)
VALUES ( 'Alden', 'Padilla', 3, 1);
INSERT INTO player (firstName, surname)
VALUES ( 'Sina', 'Parker');
INSERT INTO player (firstName, surname, coach, team)
VALUES ( 'Lyle', ' Burks', 4, 2);
INSERT INTO player (firstName, surname, coach, team)
VALUES ('Rhona', 'Anthony', 5, 3);
INSERT INTO player (firstName, surname, team)
VALUES ('Seelie', 'Harper', 5);
INSERT INTO player (firstName, surname, coach, team)
VALUES ('Harper', 'Leonards', 6, 4)
INSERT INTO player (firstName, surname, coach, team)
VALUES ('jack', 'Merril', 7, 5)
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer,mvp)
VALUES ('2011-12-03 06:01:49','53','4','2','1','4','2','1');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer,mvp)
VALUES ('2011-11-25 09:31:26','73','5','2','2','1','3','2');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer,mvp)
VALUES ('2011-12-03 19:36:34','52','1','1','1','5','4','3');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer,mvp)
VALUES ('2011-12-10 20:07:11','51','4','2','3','2','5','2');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer,mvp)
VALUES ('2011-11-15 19:19:33','83','5','2','1','3','6','1');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer)
VALUES ('2011-11-27 02:32:09','53','1','2','3','5','7');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer)
VALUES ('2011-11-24 10:31:53','51','3','1','1','4','8');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer)
VALUES ('2011-11-19 15:17:32','70','2','1','2','5','9');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer)
VALUES ('2011-12-08 18:00:51','59','2','1','3','1','10');
INSERT INTO race (dateOfRace,finalScore,pointsPenalised,raceType,course,team,observer)
VALUES ('2011-12-09 19:55:53','67','5','2','3','5','10');
Select *
From player;
Select *
From team;
Select *
From raceType;
Select *
From course;
Select *
From race;
视图脚本
USE Assignment2;
GO
PRINT 'Creating Player View'
GO
CREATE VIEW playerView AS
SELECT player.id, player.firstName + ' ' + player.surname AS 'Full name', player.team, team.name, player.coach, coach.firstName, coach.surname
FROM player
LEFT OUTER JOIN team
ON player.team = team.id
LEFT OUTER JOIN player as coach
ON player.coach = coach.id;
GO
/*
Create a view which shows the following details of all races:
• All of the columns in the race table
• The name of the race type, course and team involved in the race
• The full name of the player observing the race and the full name of the MVP (if applicable)
• A calculated column with an alias of “unpenalised_score”, which adds the points penalised to the final score
Creating this view requires a select statement using multiple joins and concatenation of names.
Make sure that you use the appropriate type of join to ensure that races without MVPs are still included in the results.
*/
-- Write your Race View here
PRINT 'Creating Race View'
GO
CREATE VIEW raceView AS
SELECT race.id, race.dateOfRace, race.raceType, raceType.name AS raceTypeName, race.course, course.name AS courseName, race.team, team.name AS teamName, race.observer, obs.firstName + ' ' + obs.surname AS observer_name, race.mvp, mvp.firstName + ' ' + mvp.surname AS mvp_name, race.pointsPenalised, race.finalScore + race.pointsPenalised AS unpenalised_score, race.finalScore
FROM race
INNER JOIN raceType
ON race.raceType = raceType.id
INNER JOIN course
ON race.course = course.id
INNER JOIN team
ON race.team = team.id
LEFT OUTER JOIN player AS mvp
ON race.mvp = mvp.id
LEFT OUTER JOIN player AS obs
ON race.observer = obs.id;
GO
SELECT *
FROM playerView
SELECT *
FROM raceView
您需要使用COUNT
select player.id,
player.firstName + ' ' + player.surname AS [Full Name],
COUNT(*)
from player JOIN race
ON player.team = race.team
GROUP BY id, player.firstName + ' ' + player.surname
HAVING COUNT(*) >= 2
更新1
SELECT MVP_NAME, COUNT(*) TotalMVP
FROM raceView
WHERE MVP IS NOT NULL
GROUP BY MVP_NAME
HAVING COUNT(*) >= 2
ORDER BY TotalMVP DESC;
- sqlfiddle demo