MySQL的问题：从另一个表填充表，但引用ID而不是名称

Question

I'm now trying to populate my 'testMatch' table (below) with data from my 'summary' table:

TESTMATCH TABLE

+------------------+--------------+------+-----+---------+-------+
| Field            | Type         | Null | Key | Default | Extra |
+------------------+--------------+------+-----+---------+-------+
| match_id         | int(11)      | NO   | PRI | NULL    |       | 
| match_date       | date         | YES  |     | NULL    |       | 
| ground           | varchar(50)  | YES  | MUL | NULL    |       | 
| homeTeam         | varchar(100) | YES  | MUL | NULL    |       | 
| awayTeam         | varchar(100) | YES  | MUL | NULL    |       | 
| matchResult      | varchar(100) | YES  | MUL | NULL    |       | 
| manOfMatch       | varchar(30)  | YES  |     | NULL    |       | 
| homeTeam_captain | int(10)      | YES  | MUL | NULL    |       | 
| homeTeam_keeper  | int(10)      | YES  | MUL | NULL    |       | 
| awayTeam_captain | int(10)      | YES  | MUL | NULL    |       | 
| awayTeam_keeper  | int(10)      | YES  | MUL | NULL    |       | 
+------------------+--------------+------+-----+---------+-------+

There is no problem populating match_id -----> manOfMatch - it is 'homeTeam_captain', 'homeTeam_keeper', 'awayTeam_captain' and 'awayTeam_keeper' that i'm having problems bringing in.

SUMMARY TABLE

mysql> DESCRIBE SUMMARY;
+-----------------+--------------+------+-----+---------+-------+
| Field           | Type         | Null | Key | Default | Extra |
+-----------------+--------------+------+-----+---------+-------+
| matchID         | int(11)      | NO   | PRI | NULL    |       | 
| Test            | int(11)      | YES  |     | NULL    |       | 
| matchDate       | date         | YES  |     | NULL    |       | 
| Ground          | varchar(50)  | YES  |     | NULL    |       | 
| HomeTeam        | varchar(100) | YES  |     | NULL    |       | 
| AwayTeam        | varchar(100) | YES  |     | NULL    |       | 
| matchResult     | varchar(50)  | YES  |     | NULL    |       | 
| MarginRuns      | int(11)      | YES  |     | NULL    |       | 
| MarginWickets   | int(11)      | YES  |     | NULL    |       | 
| ManOfMatch      | varchar(40)  | YES  |     | NULL    |       | 
| HomeTeamCaptain | varchar(30)  | YES  |     | NULL    |       | 
| HomeTeamKeeper  | varchar(30)  | YES  |     | NULL    |       | 
| AwayTeamCaptain | varchar(30)  | YES  |     | NULL    |       | 
| AwayTeamKeeper  | varchar(30)  | YES  |     | NULL    |       | 
+-----------------+--------------+------+-----+---------+-------+

I need to somehow select the data from summary, get the corresponding player_id and input the player_id into my 'testMatch'. Player table below:

PLAYERS TABLE

 mysql> describe players; +----------------+--------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +----------------+--------------+------+-----+---------+----------------+ | player_id | int(11) | NO | PRI | NULL | auto_increment | | player_surname | varchar(30) | YES | | NULL | | | team | varchar(100) | YES | MUL | NULL | | +----------------+--------------+------+-----+---------+----------------+ 

So to clarify, eg. I want to select homeTeam_captain data FROM summary table BUT not the name, I want the corresponding player_id instead.

I assume I need to use some sort of join/subqueries to get this done... i've tried finding the correct select query first to make sure i'm pulling out the right data, and I have been using the below code for testing (thanks to user Larry_Croft for helping me with this):

select matchID, player_id, player_surname, team from players p, summary s
where
s.hometeamKEEPER = p.player_surname AND s.HomeTeam = p.team ORDER BY matchID;

But this correctly brings back 65 rows (65 matches) BUT i then tried it with:

 select matchID, player_id, player_surname, team from players p, summary s where s.hometeamKEEPER = p.player_surname AND s.HomeTeam = p.team ORDER BY matchID; 

But this brings back only 61 rows (should be 65) so i must have an error in the logic.

Once I get this select to work, i then need to somehow include it into my 'INSERT INTO.....SELECT statement to put all the data into 'testMatch' table.

I hope this makes sense and thanks for your help!

Answer 1

Well for me it looks that there is eitehr a hometeamKEEPER that has a null value or that the value of hometeamKEEPER is not in the players table.

Using the following query you should be able to find the hometownKEEPER that are not in the players table:

SELECT matchID, player_id, player_surname, team 
FROM players p 
     RIGHT JOIN summary s ON p.hometeamKEEPER = p.player_surname AND 
                             s.HomeTeam = p.team
ORDER BY matchID;