Added Sql5 Q1-4

Sql5_Q1_ReportContDates_rnk_grprnk.sql

@@ -0,0 +1,34 @@
+with master_table as
+(
+    select 
+        fail_date as 'date'
+        , 'failed' as period_state
+    from 
+        Failed
+    where year(fail_date) = 2019
+    union
+    select 
+        success_date as 'date'
+        , 'succeeded' as period_state
+    from 
+        Succeeded
+    where year(success_date) = 2019
+)
+, ranking_period_state as 
+(
+    select 
+        date
+        , period_state
+        , rank() over(order by date) - rank() over(partition by period_state order by date) as diff
+    from 
+        master_table
+)
+select 
+    period_state
+    , min(date) as start_date
+    , max(date) as end_date
+from 
+    ranking_period_state
+group by 
+    diff, period_state
+order by start_date

Sql5_Q2_StudentsByGeo.sql

@@ -0,0 +1,33 @@
+with cte1 as
+(
+select 
+    name as 'America'
+    , row_number() over(order by name) as rnk
+from student
+where continent = 'America'
+order by 1
+)
+, cte2 as
+(
+select
+    name as 'Asia'
+    , row_number() over(order by name) as rnk
+from student
+where continent = 'Asia'
+order by 1
+)
+, cte3 as
+(
+select
+    name as 'Europe'
+    , row_number() over(order by name) as rnk
+from student
+where continent = 'Europe'
+order by 1
+)
+
+select 
+    cte1.America
+    , cte2.Asia
+    , cte3.Europe
+from cte2 right join cte1 on cte1.rnk = cte2.rnk left join cte3 on cte1.rnk = cte3.rnk

Sql5_Q3_AvgSalDeptCo.sql

@@ -0,0 +1,27 @@
+with company_avg as 
+(
+    select 
+        date_format(pay_date, '%Y-%m') as date_year
+        , avg(amount) as company_avg
+    from 
+        Salary
+    group by 1
+)
+, dept_avg_sal as
+(
+    select 
+        date_format(s.pay_date, '%Y-%m') as date_year
+        , e.department_id
+        , avg(s.amount) as dept_avg
+    from 
+         Salary s join Employee e on s.employee_id = e.employee_id
+    group by e.department_id, 1
+)
+
+select 
+    d.date_year as pay_month
+    , d.department_id
+    , case when c.company_avg > d.dept_avg then 'lower'
+        when c.company_avg = d.dept_avg then 'same'
+        when c.company_avg < d.dept_avg then 'higher' end as comparison
+from company_avg c join dept_avg_sal d on c.date_year = d.date_year

Sql5_Q4_GamePlayAnalysis.sql

@@ -0,0 +1,5 @@
+select 
+    player_id
+    , min(event_date) as first_login
+from Activity
+group by 1