mysql----JOIN Quiz

最新推荐文章于 2022-09-20 10:17:17 发布

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最新推荐文章于 2022-09-20 10:17:17 发布

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文章标签：数据库

本文通过具体实例演示如何使用SQL进行复杂的数据查询与分析。包括如何连接不同表来获取所需信息，选择合适的条件筛选数据，以及如何对数据进行聚合操作等实用技巧。

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JOIN quiz

game
id	mdate	stadium	team1	team2
1001	8 June 2012	National Stadium, Warsaw	POL	GRE
1002	8 June 2012	Stadion Miejski (Wroclaw)	RUS	CZE
1003	12 June 2012	Stadion Miejski (Wroclaw)	GRE	CZE
1004	12 June 2012	National Stadium, Warsaw	POL	RUS
...

goal
matchid	teamid	player	gtime
1001	POL	Robert Lewandowski	17
1001	GRE	Dimitris Salpingidis	51
1002	RUS	Alan Dzagoev	15
1001	RUS	Roman Pavlyuchenko	82
...

eteam
id	teamname	coach
POL	Poland	Franciszek Smuda
RUS	Russia	Dick Advocaat
CZE	Czech Republic	Michal Bilek
GRE	Greece	Fernando Santos
...

1. You want to find the stadium where player 'Dimitris Salpingidis' scored. Select the JOIN condition to use:

 eteam JOIN game ON (id=team1)

 eteam JOIN game ON (id=team2)

 eteam JOIN goal ON (teamid=id)

 game  JOIN goal ON (id=matchid)

 game  JOIN goal ON (team1=teamid OR team2=teamid)

2. You JOIN the tables goal and eteam in an SQL statement. Indicate the list of column names that may be used in the SELECT line:

 gtime, mdate, stadium, matchid

 mdate, stadium, id

 matchid, teamid, player, gtime, id, teamname, coach

 matchid, teamid, player, gtime, mdate, stadium, team1

 stadium, team1, team2

3. Select the code which shows players, their team and the amount of goals they scored against Greece(GRE).

SELECT player, teamid, COUNT(*)
  FROM game JOIN goal ON matchid = id
 WHERE (team1 = "GRE" OR team2 = "GRE")
   AND teamid != 'GRE'
 GROUP BY player, teamid

SELECT player, teamid, COUNT(*)
  FROM game JOIN goal ON matchid = id
 WHERE (team1 = "GRE") AND teamid != 'GRE'
 GROUP BY player, teamid

SELECT player, teamid, COUNT(*)
  FROM game JOIN goal ON matchid = id
 WHERE (team1 = "POL" OR team2 = "POL")
   AND teamid != 'POL'
 GROUP BY player, teamid

SELECT player, teamid, COUNT(*)
  FROM game JOIN goal WITH matchid = id
 WHERE (team1 = "GRE" OR team2 = "GRE")
   AND teamid != 'GRE'
 GROUP BY player, teamid

SELECT player, teamid
  FROM game JOIN goal ON matchid = id
 WHERE (team1 = "GRE" OR team2 = "GRE")
   AND teamid != 'GRE'
 GROUP BY player, teamid

4. Select the result that would be obtained from this code:

SELECT DISTINCT teamid, mdate
  FROM goal JOIN game on (matchid=id)
 WHERE mdate = '9 June 2012'

DEN	9 June 2012
GER	9 June 2012

DEN

GER

DEN	9 June 2012
DEN	9 June 2012
POL	9 June 2012
RUS	9 June 2012

GRE

CZE

POL

RUS

RUS	9 June 2012
GRE	9 June 2012
RUS	9 June 2012
CZE	9 June 2012

5. Select the code which would show the player and their team for those who have scored against Poland(POL) in National Stadium, Warsaw.

  SELECT DISTINCT player, teamid 
  FROM game JOIN goal ON matchid = id 
  WHERE stadium = 'National Stadium, Warsaw' 
 AND (team1 = 'GER' OR team2 = 'GER')
   AND teamid != 'GER'

  SELECT DISTINCT player, teamid 
   FROM game JOIN goal ON matchid = id 
  WHERE stadium = 'National Stadium, Warsaw' 
 AND (team1 = 'POL' OR team2 = 'POL')
   AND teamid != 'POL'

 
 SELECT DISTINCT player, teamid 
   FROM game JOIN goal ON matchid = id 
  WHERE stadium = 'National Stadium, Warsaw' AND teamid != 'POL'

 
 SELECT DISTINCT player, teamid 
   FROM game JOIN goal ON matchid = id 
  WHERE stadium = 'Stadion Miejski (Wroclaw)' 
 AND (team1 = 'POL' OR team2 = 'POL')
  AND teamid != 'POL'

 
 SELECT DISTINCT stadium, mdate 
   FROM game JOIN goal ON matchid = id 
  WHERE stadium = 'National Stadium, Warsaw' 
 AND (team1 = 'POL' OR team2 = 'POL')
  AND teamid != 'POL'

6. Select the code which shows the player, their team and the time they scored, for players who have played in Stadion Miejski (Wroclaw) but not against Italy(ITA).

SELECT DISTINCT player, teamid, gtime
  FROM game JOIN goal ON matchid = id
 WHERE stadium = 'National Stadium, Warsaw'
   AND (( teamid = team2 AND team1 != 'ITA') OR ( teamid = team1 AND team2 != 'ITA'))

SELECT DISTINCT player, teamid, gtime
  FROM game JOIN goal ON matchid = id
 WHERE stadium = 'Stadion Miejski (Wroclaw)'
   AND (( teamid = team2 AND team1 != 'ESP') OR ( teamid = team1 AND team2 != 'ESP'))

SELECT DISTINCT player, teamid, gtime
  FROM game JOIN goal ON matchid = id
 WHERE stadium = 'Stadion Miejski (Wroclaw)'
   AND (( teamid = team2 AND team1 != 'ITA') OR ( teamid = team1 AND team2 != 'ITA'))

SELECT DISTINCT teamid, gtime
  FROM game JOIN goal ON matchid = id
 WHERE stadium = 'Stadion Miejski (Wroclaw)'
   AND (( teamid = team2 AND team1 != 'ITA') OR ( teamid = team1 AND team2 != 'ITA'))

SELECT DISTINCT player, teamid, gtime
  FROM game JOIN goal ON matchid = id
 WHERE team1 != 'ITA' AND team2 !='ITA'

7. Select the result that would be obtained from this code:

SELECT teamname, COUNT(*)
  FROM eteam JOIN goal ON teamid = id
 GROUP BY teamname
HAVING COUNT(*) < 3

Netherlands	2
Poland	2
Republic of Ireland	1
Ukraine	2

Netherlands

Poland

Republic of Ireland

Ukraine

Poland

Republic of Ireland