SQL Exercise: List the referees with their countries for each match
SQL soccer Database: Joins Exercise-48 with Solution
48. From the following table, write a SQL query to find the name of referees for each match. Sort the result-set on match number. Return match number, country name, referee name.
Sample table: match_mastmatch_no | play_stage | play_date | results | decided_by | goal_score | venue_id | referee_id | audence | plr_of_match | stop1_sec | stop2_sec ----------+------------+------------+---------+------------+------------+----------+------------+---------+--------------+-----------+----------- 1 | G | 2016-06-11 | WIN | N | 2-1 | 20008 | 70007 | 75113 | 160154 | 131 | 242 2 | G | 2016-06-11 | WIN | N | 0-1 | 20002 | 70012 | 33805 | 160476 | 61 | 182 3 | G | 2016-06-11 | WIN | N | 2-1 | 20001 | 70017 | 37831 | 160540 | 64 | 268 4 | G | 2016-06-12 | DRAW | N | 1-1 | 20005 | 70011 | 62343 | 160128 | 0 | 185 5 | G | 2016-06-12 | WIN | N | 0-1 | 20007 | 70006 | 43842 | 160084 | 125 | 325 6 | G | 2016-06-12 | WIN | N | 1-0 | 20006 | 70014 | 33742 | 160291 | 2 | 246 7 | G | 2016-06-13 | WIN | N | 2-0 | 20003 | 70002 | 43035 | 160176 | 89 | 188 8 | G | 2016-06-13 | WIN | N | 1-0 | 20010 | 70009 | 29400 | 160429 | 360 | 182 9 | G | 2016-06-13 | DRAW | N | 1-1 | 20008 | 70010 | 73419 | 160335 | 67 | 194 10 | G | 2016-06-14 | WIN | N | 0-2 | 20004 | 70005 | 55408 | 160244 | 63 | 189 11 | G | 2016-06-14 | WIN | N | 0-2 | 20001 | 70018 | 34424 | 160197 | 61 | 305 12 | G | 2016-06-15 | DRAW | N | 1-1 | 20009 | 70004 | 38742 | 160320 | 15 | 284 13 | G | 2016-06-15 | WIN | N | 1-2 | 20003 | 70001 | 38989 | 160405 | 62 | 189 14 | G | 2016-06-15 | DRAW | N | 1-1 | 20007 | 70015 | 43576 | 160477 | 74 | 206 15 | G | 2016-06-16 | WIN | N | 2-0 | 20005 | 70013 | 63670 | 160154 | 71 | 374 16 | G | 2016-06-16 | WIN | N | 2-1 | 20002 | 70003 | 34033 | 160540 | 62 | 212 17 | G | 2016-06-16 | WIN | N | 0-2 | 20004 | 70016 | 51043 | 160262 | 7 | 411 18 | G | 2016-06-17 | DRAW | N | 0-0 | 20008 | 70008 | 73648 | 160165 | 6 | 208 19 | G | 2016-06-17 | WIN | N | 1-0 | 20010 | 70007 | 29600 | 160248 | 2 | 264 20 | G | 2016-06-17 | DRAW | N | 2-2 | 20009 | 70005 | 38376 | 160086 | 71 | 280 21 | G | 2016-06-18 | WIN | N | 3-0 | 20006 | 70010 | 33409 | 160429 | 84 | 120 22 | G | 2016-06-18 | WIN | N | 3-0 | 20001 | 70004 | 39493 | 160064 | 11 | 180 23 | G | 2016-06-18 | DRAW | N | 1-1 | 20005 | 70015 | 60842 | 160230 | 61 | 280 24 | G | 2016-06-19 | DRAW | N | 0-0 | 20007 | 70011 | 44291 | 160314 | 3 | 200 25 | G | 2016-06-20 | WIN | N | 0-1 | 20004 | 70016 | 49752 | 160005 | 125 | 328 26 | G | 2016-06-20 | DRAW | N | 0-0 | 20003 | 70001 | 45616 | 160463 | 60 | 122 27 | G | 2016-06-21 | WIN | N | 0-3 | 20010 | 70006 | 28840 | 160544 | 62 | 119 28 | G | 2016-06-21 | DRAW | N | 0-0 | 20009 | 70012 | 39051 | 160392 | 62 | 301 29 | G | 2016-06-21 | WIN | N | 0-1 | 20005 | 70017 | 58874 | 160520 | 29 | 244 30 | G | 2016-06-21 | WIN | N | 0-1 | 20007 | 70018 | 44125 | 160177 | 21 | 195 31 | G | 2016-06-22 | WIN | N | 0-2 | 20002 | 70013 | 32836 | 160504 | 60 | 300 32 | G | 2016-06-22 | WIN | N | 2-1 | 20001 | 70008 | 37245 | 160085 | 70 | 282 33 | G | 2016-06-22 | WIN | N | 2-1 | 20008 | 70009 | 68714 | 160220 | 7 | 244 34 | G | 2016-06-22 | DRAW | N | 3-3 | 20004 | 70002 | 55514 | 160322 | 70 | 185 35 | G | 2016-06-23 | WIN | N | 0-1 | 20003 | 70014 | 44268 | 160333 | 79 | 221 36 | G | 2016-06-23 | WIN | N | 0-1 | 20006 | 70003 | 34011 | 160062 | 63 | 195 37 | R | 2016-06-25 | WIN | P | 1-1 | 20009 | 70005 | 38842 | 160476 | 126 | 243 38 | R | 2016-06-25 | WIN | N | 1-0 | 20007 | 70002 | 44342 | 160547 | 5 | 245 39 | R | 2016-06-26 | WIN | N | 0-1 | 20002 | 70012 | 33523 | 160316 | 61 | 198 40 | R | 2016-06-26 | WIN | N | 2-1 | 20004 | 70011 | 56279 | 160160 | 238 | 203 41 | R | 2016-06-26 | WIN | N | 3-0 | 20003 | 70009 | 44312 | 160173 | 62 | 124 42 | R | 2016-06-27 | WIN | N | 0-4 | 20010 | 70010 | 28921 | 160062 | 3 | 133 43 | R | 2016-06-27 | WIN | N | 2-0 | 20008 | 70004 | 76165 | 160235 | 63 | 243 44 | R | 2016-06-28 | WIN | N | 1-2 | 20006 | 70001 | 33901 | 160217 | 5 | 199 45 | Q | 2016-07-01 | WIN | P | 1-1 | 20005 | 70003 | 62940 | 160316 | 58 | 181 46 | Q | 2016-07-02 | WIN | N | 3-1 | 20003 | 70001 | 45936 | 160550 | 14 | 182 47 | Q | 2016-07-03 | WIN | P | 1-1 | 20001 | 70007 | 38764 | 160163 | 63 | 181 48 | Q | 2016-07-04 | WIN | N | 5-2 | 20008 | 70008 | 76833 | 160159 | 16 | 125 49 | S | 2016-07-07 | WIN | N | 2-0 | 20004 | 70006 | 55679 | 160322 | 2 | 181 50 | S | 2016-07-08 | WIN | N | 2-0 | 20005 | 70011 | 64078 | 160160 | 126 | 275 51 | F | 2016-07-11 | WIN | N | 1-0 | 20008 | 70005 | 75868 | 160307 | 161 | 181Sample table: referee_mast
referee_id | referee_name | country_id ------------+-------------------------+------------ 70001 | Damir Skomina | 1225 70002 | Martin Atkinson | 1206 70003 | Felix Brych | 1208 70004 | Cuneyt Cakir | 1222 70005 | Mark Clattenburg | 1206 70006 | Jonas Eriksson | 1220 70007 | Viktor Kassai | 1209 70008 | Bjorn Kuipers | 1226 70009 | Szymon Marciniak | 1213 70010 | Milorad Mazic | 1227 70011 | Nicola Rizzoli | 1211 70012 | Carlos Velasco Carballo | 1219 70013 | William Collum | 1228 70014 | Ovidiu Hategan | 1216 70015 | Sergei Karasev | 1217 70016 | Pavel Kralovec | 1205 70017 | Svein Oddvar Moen | 1229 70018 | Clement Turpin | 1207Sample 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 match number, country name, and referee name for each match
SELECT
a.match_no, -- Selecting the match number from the match_mast table
b.country_name, -- Selecting the country name from the soccer_country table
c.referee_name -- Selecting the referee name from the referee_mast table
FROM
match_mast a -- Specifying the match_mast table with alias 'a'
JOIN
referee_mast c ON a.referee_id = c.referee_id -- Joining the match_mast table with the referee_mast table on the referee ID
JOIN
soccer_country b ON c.country_id = b.country_id -- Joining the referee_mast table with the soccer_country table on the country ID
-- Ordering the results by match number
ORDER BY
a.match_no;
Sample Output:
match_no | country_name | referee_name ----------+----------------+------------------------- 1 | Hungary | Viktor Kassai 2 | Spain | Carlos Velasco Carballo 3 | Norway | Svein Oddvar Moen 4 | Italy | Nicola Rizzoli 5 | Sweden | Jonas Eriksson 6 | Romania | Ovidiu Hategan 7 | England | Martin Atkinson 8 | Poland | Szymon Marciniak 9 | Serbia | Milorad Mazic 10 | England | Mark Clattenburg 11 | France | Clement Turpin 12 | Turkey | Cuneyt Cakir 13 | Slovenia | Damir Skomina 14 | Russia | Sergei Karasev 15 | Scotland | William Collum 16 | Germany | Felix Brych 17 | Czech Republic | Pavel Kralovec 18 | Netherlands | Bjorn Kuipers 19 | Hungary | Viktor Kassai 20 | England | Mark Clattenburg 21 | Serbia | Milorad Mazic 22 | Turkey | Cuneyt Cakir 23 | Russia | Sergei Karasev 24 | Italy | Nicola Rizzoli 25 | Czech Republic | Pavel Kralovec 26 | Slovenia | Damir Skomina 27 | Sweden | Jonas Eriksson 28 | Spain | Carlos Velasco Carballo 29 | Norway | Svein Oddvar Moen 30 | France | Clement Turpin 31 | Scotland | William Collum 32 | Netherlands | Bjorn Kuipers 33 | Poland | Szymon Marciniak 34 | England | Martin Atkinson 35 | Romania | Ovidiu Hategan 36 | Germany | Felix Brych 37 | England | Mark Clattenburg 38 | England | Martin Atkinson 39 | Spain | Carlos Velasco Carballo 40 | Italy | Nicola Rizzoli 41 | Poland | Szymon Marciniak 42 | Serbia | Milorad Mazic 43 | Turkey | Cuneyt Cakir 44 | Slovenia | Damir Skomina 45 | Germany | Felix Brych 46 | Slovenia | Damir Skomina 47 | Hungary | Viktor Kassai 48 | Netherlands | Bjorn Kuipers 49 | Sweden | Jonas Eriksson 50 | Italy | Nicola Rizzoli 51 | England | Mark Clattenburg (51 rows)
Code Explanation:
The said query in SQL that selects the match number, country name, and referee name for each match in the match_mast table.
The JOIN clause in this query then joins the match_mast and referee_mast tables based on the referee_id column and joins the results with soccer_country tables based on the country_id column.
The query then orders the results by match number in ascending order using the ORDER BY clause.
Alternative Solution:
Correlated Subquery:
-- Selecting match number, country name, and referee name for each match
SELECT
a.match_no, -- Selecting the match number from the match_mast table
( -- Subquery to select the country name associated with the referee for each match
SELECT b.country_name -- Selecting the country name from the soccer_country table
FROM soccer_country b -- Specifying the soccer_country table with alias 'b'
JOIN referee_mast c ON b.country_id = c.country_id -- Joining the soccer_country table with the referee_mast table on the country ID
WHERE a.referee_id = c.referee_id -- Matching the referee ID with the one in the outer query
) AS country_name, -- Alias for the country name subquery result
( -- Subquery to select the referee name for each match
SELECT c.referee_name -- Selecting the referee name from the referee_mast table
FROM referee_mast c -- Specifying the referee_mast table with alias 'c'
WHERE a.referee_id = c.referee_id -- Matching the referee ID with the one in the outer query
) AS referee_name -- Alias for the referee name subquery result
FROM
match_mast a -- Specifying the match_mast table with alias 'a'
-- Ordering the results by match number
ORDER BY
a.match_no;
Explanation:
This query uses correlated subqueries to retrieve the country name and referee name based on the referee ID associated with each match. The outer query selects the match number.
Relational Algebra Expression:
Relational Algebra Tree:
Practice Online
Sample Database: soccer
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Previous SQL Exercise: Countries where assistant referees assist most matches.
Next SQL Exercise: The number of matches each referee has managed.
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