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SQL Exercise: Each match assistant referee and their country

SQL soccer Database: Joins Exercise-45 with Solution

45. From the following table, write a SQL query to find the assistant referees. Return match number, country name, assistant referee name.

Sample table: match_details
 match_no | play_stage | team_id | win_lose | decided_by | goal_score | penalty_score | ass_ref | player_gk
----------+------------+---------+----------+------------+------------+---------------+---------+-----------
        1 | G          |    1207 | W        | N          |          2 |               |   80016 |    160140
        1 | G          |    1216 | L        | N          |          1 |               |   80020 |    160348
        2 | G          |    1201 | L        | N          |          0 |               |   80003 |    160001
        2 | G          |    1221 | W        | N          |          1 |               |   80023 |    160463
        3 | G          |    1224 | W        | N          |          2 |               |   80031 |    160532
        3 | G          |    1218 | L        | N          |          1 |               |   80025 |    160392
        4 | G          |    1206 | D        | N          |          1 |               |   80008 |    160117
        4 | G          |    1217 | D        | N          |          1 |               |   80019 |    160369
        5 | G          |    1222 | L        | N          |          0 |               |   80011 |    160486
        5 | G          |    1204 | W        | N          |          1 |               |   80022 |    160071
        6 | G          |    1213 | W        | N          |          1 |               |   80036 |    160279
        6 | G          |    1212 | L        | N          |          0 |               |   80029 |    160256
        7 | G          |    1208 | W        | N          |          2 |               |   80014 |    160163
        7 | G          |    1223 | L        | N          |          0 |               |   80006 |    160508
        8 | G          |    1219 | W        | N          |          1 |               |   80018 |    160416
        8 | G          |    1205 | L        | N          |          0 |               |   80012 |    160093
        9 | G          |    1215 | D        | N          |          1 |               |   80017 |    160324
        9 | G          |    1220 | D        | N          |          1 |               |   80010 |    160439
       10 | G          |    1203 | L        | N          |          0 |               |   80004 |    160047
       10 | G          |    1211 | W        | N          |          2 |               |   80007 |    160231
       11 | G          |    1202 | L        | N          |          0 |               |   80026 |    160024
       11 | G          |    1209 | W        | N          |          2 |               |   80028 |    160187
       12 | G          |    1214 | D        | N          |          1 |               |   80009 |    160302
       12 | G          |    1210 | D        | N          |          1 |               |   80015 |    160208
       13 | G          |    1217 | L        | N          |          1 |               |   80001 |    160369
       13 | G          |    1218 | W        | N          |          2 |               |   80002 |    160392
       14 | G          |    1216 | D        | N          |          1 |               |   80030 |    160348
       14 | G          |    1221 | D        | N          |          1 |               |   80032 |    160463
       15 | G          |    1207 | W        | N          |          2 |               |   80033 |    160140
       15 | G          |    1201 | L        | N          |          0 |               |   80027 |    160001
       16 | G          |    1206 | W        | N          |          2 |               |   80005 |    160117
       16 | G          |    1224 | L        | N          |          1 |               |   80013 |    160531
       17 | G          |    1223 | L        | N          |          0 |               |   80035 |    160508
       17 | G          |    1212 | W        | N          |          2 |               |   80034 |    160256
       18 | G          |    1208 | D        | N          |          0 |               |   80021 |    160163
       18 | G          |    1213 | D        | N          |          0 |               |   80024 |    160278
       19 | G          |    1211 | W        | N          |          1 |               |   80016 |    160231
       19 | G          |    1220 | L        | N          |          0 |               |   80020 |    160439
       20 | G          |    1205 | D        | N          |          2 |               |   80004 |    160093
       20 | G          |    1204 | D        | N          |          2 |               |   80007 |    160071
       21 | G          |    1219 | W        | N          |          3 |               |   80017 |    160416
       21 | G          |    1222 | L        | N          |          0 |               |   80010 |    160486
       22 | G          |    1203 | W        | N          |          3 |               |   80009 |    160047
       22 | G          |    1215 | L        | N          |          0 |               |   80015 |    160324
       23 | G          |    1210 | D        | N          |          1 |               |   80030 |    160208
       23 | G          |    1209 | D        | N          |          1 |               |   80032 |    160187
       24 | G          |    1214 | D        | N          |          0 |               |   80008 |    160302
       24 | G          |    1202 | D        | N          |          0 |               |   80019 |    160024
       25 | G          |    1216 | L        | N          |          0 |               |   80035 |    160348
       25 | G          |    1201 | W        | N          |          1 |               |   80034 |    160001
       26 | G          |    1221 | D        | N          |          0 |               |   80001 |    160463
       26 | G          |    1207 | D        | N          |          0 |               |   80002 |    160140
       27 | G          |    1217 | L        | N          |          0 |               |   80011 |    160369
       27 | G          |    1224 | W        | N          |          3 |               |   80022 |    160531
       28 | G          |    1218 | D        | N          |          0 |               |   80003 |    160392
       28 | G          |    1206 | D        | N          |          0 |               |   80023 |    160117
       29 | G          |    1223 | L        | N          |          0 |               |   80031 |    160508
       29 | G          |    1213 | W        | N          |          1 |               |   80025 |    160278
       30 | G          |    1212 | L        | N          |          0 |               |   80026 |    160256
       30 | G          |    1208 | W        | N          |          1 |               |   80028 |    160163
       31 | G          |    1205 | L        | N          |          0 |               |   80033 |    160093
       31 | G          |    1222 | W        | N          |          2 |               |   80027 |    160486
       32 | G          |    1204 | W        | N          |          2 |               |   80021 |    160071
       32 | G          |    1219 | L        | N          |          1 |               |   80024 |    160416
       33 | G          |    1210 | W        | N          |          2 |               |   80018 |    160208
       33 | G          |    1202 | L        | N          |          1 |               |   80012 |    160024
       34 | G          |    1209 | D        | N          |          3 |               |   80014 |    160187
       34 | G          |    1214 | D        | N          |          3 |               |   80006 |    160302
       35 | G          |    1211 | L        | N          |          0 |               |   80036 |    160233
       35 | G          |    1215 | W        | N          |          1 |               |   80029 |    160324
       36 | G          |    1220 | L        | N          |          0 |               |   80005 |    160439
       36 | G          |    1203 | W        | N          |          1 |               |   80013 |    160047
       37 | R          |    1221 | L        | P          |          1 |             4 |   80004 |    160463
       37 | R          |    1213 | W        | P          |          1 |             5 |   80007 |    160278
       38 | R          |    1224 | W        | N          |          1 |               |   80014 |    160531
       38 | R          |    1212 | L        | N          |          0 |               |   80006 |    160256
       39 | R          |    1204 | L        | N          |          0 |               |   80003 |    160071
       39 | R          |    1214 | W        | N          |          1 |               |   80023 |    160302
       40 | R          |    1207 | W        | N          |          2 |               |   80008 |    160140
       40 | R          |    1215 | L        | N          |          1 |               |   80019 |    160324
       41 | R          |    1208 | W        | N          |          3 |               |   80018 |    160163
       41 | R          |    1218 | L        | N          |          0 |               |   80012 |    160392
       42 | R          |    1209 | L        | N          |          0 |               |   80017 |    160187
       42 | R          |    1203 | W        | N          |          4 |               |   80010 |    160047
       43 | R          |    1211 | W        | N          |          2 |               |   80009 |    160231
       43 | R          |    1219 | L        | N          |          0 |               |   80015 |    160416
       44 | R          |    1206 | L        | N          |          1 |               |   80001 |    160117
       44 | R          |    1210 | W        | N          |          2 |               |   80002 |    160208
       45 | Q          |    1213 | L        | P          |          1 |             3 |   80005 |    160278
       45 | Q          |    1214 | W        | P          |          1 |             5 |   80013 |    160302
       46 | Q          |    1224 | W        | N          |          3 |               |   80001 |    160531
       46 | Q          |    1203 | L        | N          |          1 |               |   80002 |    160047
       47 | Q          |    1208 | W        | P          |          1 |             6 |   80016 |    160163
       47 | Q          |    1211 | L        | P          |          1 |             5 |   80020 |    160231
       48 | Q          |    1207 | W        | N          |          5 |               |   80021 |    160140
       48 | Q          |    1210 | L        | N          |          2 |               |   80024 |    160208
       49 | S          |    1214 | W        | N          |          2 |               |   80011 |    160302
       49 | S          |    1224 | L        | N          |          0 |               |   80022 |    160531
       50 | S          |    1207 | W        | N          |          2 |               |   80008 |    160140
       50 | S          |    1208 | L        | N          |          1 |               |   80019 |    160163
       51 | F          |    1214 | W        | N          |          1 |               |   80004 |    160302
       51 | F          |    1207 | L        | N          |          0 |               |   80007 |    160140
Sample table: asst_referee_mast
 ass_ref_id |       ass_ref_name       | country_id
------------+--------------------------+------------
      80034 | Tomas Mokrusch           |       1205
      80038 | Martin Wilczek           |       1205
      80004 | Simon Beck               |       1206
      80006 | Stephen Child            |       1206
      80007 | Jake Collin              |       1206
      80014 | Mike Mullarkey           |       1206
      80026 | Frederic Cano            |       1207
      80028 | Nicolas Danos            |       1207
      80005 | Mark Borsch              |       1208
      80013 | Stefan Lupp              |       1208
      80016 | Gyorgy Ring              |       1209
      80020 | Vencel Toth              |       1209
      80033 | Damien McGraith          |       1215
      80008 | Elenito Di Liberatore    |       1211
      80019 | Mauro Tonolini           |       1211
      80021 | Sander van Roekel        |       1226
      80024 | Erwin Zeinstra           |       1226
      80025 | Frank Andas              |       1229
      80031 | Kim Haglund              |       1229
      80012 | Tomasz Listkiewicz       |       1213
      80018 | Pawel Sokolnicki         |       1213
      80029 | Sebastian Gheorghe       |       1216
      80036 | Octavian Sovre           |       1216
      80030 | Nikolay Golubev          |       1217
      80032 | Tikhon Kalugin           |       1217
      80037 | Anton Averyanov          |       1217
      80027 | Frank Connor             |       1228
      80010 | Dalibor Durdevic         |       1227
      80017 | Milovan Ristic           |       1227
      80035 | Roman Slysko             |       1218
      80001 | Jure Praprotnik          |       1225
      80002 | Robert Vukan             |       1225
      80003 | Roberto Alonso Fernandez |       1219
      80023 | Juan Yuste Jimenez       |       1219
      80011 | Mathias Klasenius        |       1220
      80022 | Daniel Warnmark          |       1220
      80009 | Bahattin Duran           |       1222
      80015 | Tarik Ongun              |       1222
Sample table: soccer_country
 country_id | country_abbr |    country_name
------------+--------------+---------------------
       1201 | ALB          | Albania
       1202 | AUT          | Austria
       1203 | BEL          | Belgium
       1204 | CRO          | Croatia
       1205 | CZE          | Czech Republic
       1206 | ENG          | England
       1207 | FRA          | France
       1208 | GER          | Germany
       1209 | HUN          | Hungary
       1210 | ISL          | Iceland
       1211 | ITA          | Italy
       1212 | NIR          | Northern Ireland
       1213 | POL          | Poland
       1214 | POR          | Portugal
       1215 | IRL          | Republic of Ireland
       1216 | ROU          | Romania
       1217 | RUS          | Russia
       1218 | SVK          | Slovakia
       1219 | ESP          | Spain
       1220 | SWE          | Sweden
       1221 | SUI          | Switzerland
       1222 | TUR          | Turkey
       1223 | UKR          | Ukraine
       1224 | WAL          | Wales
       1225 | SLO          | Slovenia
       1226 | NED          | Netherlands
       1227 | SRB          | Serbia
       1228 | SCO          | Scotland
       1229 | NOR          | Norway

Sample Solution:

SQL Code:

-- Selecting the match number, country name, and assistant referee name for each match
SELECT 
    a.match_no, -- Selecting the match number from the match_details table
    b.country_name, -- Selecting the country name from the soccer_country table
    c.ass_ref_name -- Selecting the assistant referee name from the asst_referee_mast table
FROM 
    match_details a -- Specifying the match_details table with alias 'a'
JOIN 
    asst_referee_mast c -- Joining the asst_referee_mast table with alias 'c' to match_details table
ON 
    a.ass_ref = c.ass_ref_id -- Joining on the assistant referee ID from match_details and asst_referee_mast tables
JOIN 
    soccer_country b -- Joining the soccer_country table with alias 'b' to asst_referee_mast table
ON 
    c.country_id = b.country_id -- Joining on the country ID from asst_referee_mast and soccer_country tables
	-- Ordering the results by match number
ORDER BY 
    a.match_no; 

Sample Output:

 match_no |    country_name     |       ass_ref_name
----------+---------------------+--------------------------
        1 | Hungary             | Gyorgy Ring
        1 | Hungary             | Vencel Toth
        2 | Spain               | Juan Yuste Jimenez
        2 | Spain               | Roberto Alonso Fernandez
        3 | Norway              | Frank Andas
        3 | Norway              | Kim Haglund
        4 | Italy               | Mauro Tonolini
        4 | Italy               | Elenito Di Liberatore
        5 | Sweden              | Daniel Warnmark
        5 | Sweden              | Mathias Klasenius
        6 | Romania             | Octavian Sovre
        6 | Romania             | Sebastian Gheorghe
        7 | England             | Stephen Child
        7 | England             | Mike Mullarkey
        8 | Poland              | Pawel Sokolnicki
        8 | Poland              | Tomasz Listkiewicz
        9 | Serbia              | Dalibor Durdevic
        9 | Serbia              | Milovan Ristic
       10 | England             | Jake Collin
       10 | England             | Simon Beck
       11 | France              | Nicolas Danos
       11 | France              | Frederic Cano
       12 | Turkey              | Tarik Ongun
       12 | Turkey              | Bahattin Duran
       13 | Slovenia            | Robert Vukan
       13 | Slovenia            | Jure Praprotnik
       14 | Russia              | Nikolay Golubev
       14 | Russia              | Tikhon Kalugin
       15 | Scotland            | Frank Connor
       15 | Republic of Ireland | Damien McGraith
       16 | Germany             | Mark Borsch
       16 | Germany             | Stefan Lupp
       17 | Slovakia            | Roman Slysko
       17 | Czech Republic      | Tomas Mokrusch
       18 | Netherlands         | Erwin Zeinstra
       18 | Netherlands         | Sander van Roekel
       19 | Hungary             | Gyorgy Ring
       19 | Hungary             | Vencel Toth
       20 | England             | Jake Collin
       20 | England             | Simon Beck
       21 | Serbia              | Milovan Ristic
       21 | Serbia              | Dalibor Durdevic
       22 | Turkey              | Tarik Ongun
       22 | Turkey              | Bahattin Duran
       23 | Russia              | Tikhon Kalugin
       23 | Russia              | Nikolay Golubev
       24 | Italy               | Elenito Di Liberatore
       24 | Italy               | Mauro Tonolini
       25 | Slovakia            | Roman Slysko
       25 | Czech Republic      | Tomas Mokrusch
       26 | Slovenia            | Robert Vukan
       26 | Slovenia            | Jure Praprotnik
       27 | Sweden              | Daniel Warnmark
       27 | Sweden              | Mathias Klasenius
       28 | Spain               | Juan Yuste Jimenez
       28 | Spain               | Roberto Alonso Fernandez
       29 | Norway              | Kim Haglund
       29 | Norway              | Frank Andas
       30 | France              | Nicolas Danos
       30 | France              | Frederic Cano
       31 | Scotland            | Frank Connor
       31 | Republic of Ireland | Damien McGraith
       32 | Netherlands         | Erwin Zeinstra
       32 | Netherlands         | Sander van Roekel
       33 | Poland              | Pawel Sokolnicki
       33 | Poland              | Tomasz Listkiewicz
       34 | England             | Mike Mullarkey
       34 | England             | Stephen Child
       35 | Romania             | Octavian Sovre
       35 | Romania             | Sebastian Gheorghe
       36 | Germany             | Mark Borsch
       36 | Germany             | Stefan Lupp
       37 | England             | Simon Beck
       37 | England             | Jake Collin
       38 | England             | Stephen Child
       38 | England             | Mike Mullarkey
       39 | Spain               | Juan Yuste Jimenez
       39 | Spain               | Roberto Alonso Fernandez
       40 | Italy               | Elenito Di Liberatore
       40 | Italy               | Mauro Tonolini
       41 | Poland              | Tomasz Listkiewicz
       41 | Poland              | Pawel Sokolnicki
       42 | Serbia              | Milovan Ristic
       42 | Serbia              | Dalibor Durdevic
       43 | Turkey              | Bahattin Duran
       43 | Turkey              | Tarik Ongun
       44 | Slovenia            | Jure Praprotnik
       44 | Slovenia            | Robert Vukan
       45 | Germany             | Mark Borsch
       45 | Germany             | Stefan Lupp
       46 | Slovenia            | Jure Praprotnik
       46 | Slovenia            | Robert Vukan
       47 | Hungary             | Vencel Toth
       47 | Hungary             | Gyorgy Ring
       48 | Netherlands         | Sander van Roekel
       48 | Netherlands         | Erwin Zeinstra
       49 | Sweden              | Daniel Warnmark
       49 | Sweden              | Mathias Klasenius
       50 | Italy               | Elenito Di Liberatore
       50 | Italy               | Mauro Tonolini
       51 | England             | Simon Beck
       51 | England             | Jake Collin
(102 rows)

Code Explanation:

The said query in SQL that retrieves the match number, the country name of the assistant referee, and the name of the assistant referee from the tables 'match_details', 'asst_referee_mast', and 'soccer_country'.
The JOIN clause joins the 'match_details' table with the 'asst_referee_mast' table based on the "ass_ref" and the "ass_ref_id" columns respectively. It then joins the result with the 'soccer_country' table on the "country_id" column.
This orders the results by the match number in ascending order.

Alternative Solutions:

Using Subqueries:

-- Selecting the match number, country name of the assistant referee, and assistant referee name for each match
SELECT 
    md.match_no, -- Selecting the match number from the match_details table
    ( -- Subquery to fetch the country name of the assistant referee
        SELECT 
            sc.country_name -- Selecting the country name from the soccer_country table
        FROM 
            soccer_country sc -- Specifying the soccer_country table with alias 'sc'
        WHERE 
            sc.country_id = ( -- Matching the country ID with the one in the asst_referee_mast table
                SELECT 
                    arm.country_id -- Selecting the country ID from the asst_referee_mast table
                FROM 
                    asst_referee_mast arm -- Specifying the asst_referee_mast table with alias 'arm'
                WHERE 
                    arm.ass_ref_id = md.ass_ref -- Matching the assistant referee ID from match_details
            )
    ) as country_name, -- Alias for the country name subquery result
    ( -- Subquery to fetch the assistant referee name
        SELECT 
            arm.ass_ref_name -- Selecting the assistant referee name from the asst_referee_mast table
        FROM 
            asst_referee_mast arm -- Specifying the asst_referee_mast table with alias 'arm'
        WHERE 
            arm.ass_ref_id = md.ass_ref -- Matching the assistant referee ID from match_details
    ) as ass_ref_name -- Alias for the assistant referee name subquery result
FROM 
    match_details md -- Specifying the match_details table with alias 'md'
	-- Ordering the results by match number
ORDER BY 
    md.match_no; 

Explanation:

This query uses correlated subqueries to retrieve the country name and assistant referee name based on their respective IDs. It selects the match number along with these values and orders the results by match number.

Using Subqueries with INNER JOIN:

-- Selecting the match number, country name of the assistant referee, and assistant referee name for each match
SELECT 
    md.match_no, -- Selecting the match number from the match_details table
    ( -- Subquery to fetch the country name of the assistant referee
        SELECT 
            sc.country_name -- Selecting the country name from the soccer_country table
        FROM 
            soccer_country sc -- Specifying the soccer_country table with alias 'sc'
        JOIN 
            asst_referee_mast arm ON arm.country_id = sc.country_id -- Joining the asst_referee_mast table with the soccer_country table based on country ID
        WHERE 
            arm.ass_ref_id = md.ass_ref -- Matching the assistant referee ID from match_details
    ) as country_name, -- Alias for the country name subquery result
    ( -- Subquery to fetch the assistant referee name
        SELECT 
            arm.ass_ref_name -- Selecting the assistant referee name from the asst_referee_mast table
        FROM 
            asst_referee_mast arm -- Specifying the asst_referee_mast table with alias 'arm'
        WHERE 
            arm.ass_ref_id = md.ass_ref -- Matching the assistant referee ID from match_details
    ) as ass_ref_name -- Alias for the assistant referee name subquery result
FROM 
    match_details md -- Specifying the match_details table with alias 'md'
	-- Ordering the results by match number
ORDER BY 
    md.match_no; 

Explanation:

This query uses subqueries with INNER JOINs to retrieve the country name and assistant referee name. It selects the match number along with these values and orders the results by match number.

Relational Algebra Expression:

Relational Algebra Expression: List the name of assistant referees with their countries for each matches.

Relational Algebra Tree:

Relational Algebra Tree: List the name of assistant referees with their countries for each matches.

Practice Online


Sample Database: soccer

soccer database relationship structure

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Next SQL Exercise: Assistant referees of each countries assists matches.

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