Sql4 Done

Friend_Request.sql

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+WITH CTE AS (SELECT REQUESTER_ID AS ID FROM REQUESTACCEPTED UNION ALL SELECT ACCEPTER_ID AS ID FROM REQUESTACCEPTED)
+SELECT ID, COUNT(ID) AS NUM FROM CTE GROUP BY ID ORDER BY NUM DESC LIMIT 1;

League_Statistics.sql

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+WITH CTE AS (
+    SELECT home_team_id as id ,home_team_goals as hg, away_team_goals as ag from matches 
+    union all
+    select away_team_id as id, away_team_goals as hg, home_team_goals as ag from matches
+), POINTS AS (
+select id,case when hg>ag then 3
+when hg=ag then 1 else 0 end as points,hg,ag from CTE)
+select teams.team_name,count(id)as matches_played,sum(points) as points, sum(hg) as goal_for, sum(ag) as goal_against,sum(hg)- sum(ag) as goal_diff from points left join teams on teams.team_id = points.id group by id order by points desc, goal_diff desc, team_name;

Number_of_seniors_Juniors.sql

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+with seniors as 
+(
+select employee_id,
+70000 - rolling_sum as budget_left
+from
+(select *,
+sum(salary) over(order by salary asc) as rolling_sum
+from Candidates
+where experience = 'Senior') a
+where rolling_sum <= 70000
+),
+
+juniors as 
+(
+select a.employee_id
+from
+(select *,
+sum(salary) over(order by salary asc) as rolling_sum
+from Candidates
+where experience = 'Junior') a
+where rolling_sum <= (select coalesce(min(budget_left), 70000) from seniors)
+)
+
+select 'Senior' as experience,
+coalesce(count(employee_id), 0) as accepted_candidates
+from seniors
+union all
+select 'Junior' as experience,
+coalesce(count(employee_id), 0) as accepted_candidates
+from juniors;

Sales_Person.sql

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+select salesperson.name
+from orders o join company c on (o.com_id = c.com_id and c.name = 'RED')
+right join salesperson on salesperson.sales_id = o.sales_id
+where o.sales_id is null