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SQL Exercise: Find the match in which Germany played against Poland

SQL soccer Database: Subqueries Exercise-4 with Solution

4. From the following tables, write a SQL query to find the match number in which Germany played against Poland. Group the result set on match number. Return match number.

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: 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:

-- This SQL query retrieves match numbers from the 'match_details' table
-- where the teams are either Germany or Poland, and each match involves both teams.

SELECT match_no 
-- Selects the 'match_no' column.
FROM match_details 
-- 'match_details' is the name of the table being queried.
WHERE team_id = (
-- The WHERE clause filters rows where 'team_id' matches the country ID for Germany in the subquery.
    SELECT country_id 
    -- The subquery selects the 'country_id' column.
    FROM soccer_country 
    -- 'soccer_country' is the name of the table involved in the subquery.
    WHERE country_name = 'Germany'
) 
OR team_id = (
-- The OR condition allows for rows where 'team_id' matches the country ID for Poland in the subquery.
    SELECT country_id 
    -- The subquery selects the 'country_id' column.
    FROM soccer_country 
    -- 'soccer_country' is the name of the table involved in the subquery.
    WHERE country_name = 'Poland'
) 
GROUP BY match_no 
-- Groups the results by 'match_no'.
HAVING COUNT(DISTINCT team_id) = 2;
-- The HAVING clause filters groups where the count of distinct 'team_id' values is equal to 2.

Sample Output:

 match_no
----------
       18
(1 row)

Code Explanation:

The said query in SQL that selects the match number from the 'match_details' table where either the team_id is Germany's country_id or Poland's country_id and there are two distinct team_ids associated with that match.
The WHERE clause filters the results to only include rows where the "team_id" column is equal to either Germany's country_id or Poland's country_id.
The GROUP BY clause groups the results by the "match_no" column.
The HAVING clause filters the results to only include groups where there are two distinct values of the "team_id" column.
So, this query will return the match numbers for matches where Germany or Poland participated and there were exactly two teams in the match.

Alternative Solutions:

Using JOIN and WHERE:


SELECT md.match_no 
FROM match_details md
JOIN soccer_country sc ON md.team_id = sc.country_id
WHERE sc.country_name IN ('Germany', 'Poland')
GROUP BY md.match_no
HAVING COUNT(DISTINCT md.team_id) = 2;

Explanation:

This query joins match_details with soccer_country based on the team_id and country_id relation. It then filters for matches involving Germany or Poland, groups the results by match number, and ensures that both teams are present in the match.

Using EXISTS:


SELECT match_no
FROM match_details md1
WHERE team_id = (
    SELECT country_id 
    FROM soccer_country 
    WHERE country_name='Germany'
)
AND EXISTS (
    SELECT 1
    FROM match_details md2
    WHERE md2.match_no = md1.match_no
    AND md2.team_id = (
        SELECT country_id 
        FROM soccer_country 
        WHERE country_name='Poland'
    )
);

Explanation:

This query uses two correlated subqueries to find matches where Germany and Poland both participated.

Using INTERSECT:


SELECT match_no 
FROM match_details 
WHERE team_id = (
    SELECT country_id 
    FROM soccer_country 
    WHERE country_name='Germany'
)
INTERSECT
SELECT match_no 
FROM match_details 
WHERE team_id = (
    SELECT country_id 
    FROM soccer_country 
    WHERE country_name='Poland'
);

Explanation:

This query uses the INTERSECT operator to find matches that involve both Germany and Poland.

Practice Online


Sample Database: soccer

soccer database relationship structure

Query Visualization:

Duration:

Query visualization of Find the match no in which Germany played against Poland - Duration

Rows:

Query visualization of Find the match no in which Germany played against Poland - Rows

Cost:

Query visualization of Find the match no in which Germany played against Poland - Cost

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Previous SQL Exercise: Find which was the highest audience match.
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