From b36f4b1d2f56ee1197991fb7b0a5961dabdf9537 Mon Sep 17 00:00:00 2001
From: Zaid Roshan Mayers <zaidmayers@gmail.com>
Date: Fri, 13 Dec 2024 21:48:15 -0500
Subject: [PATCH 1/3] Added solutions for NumberOfPassengers.sql

---
 NumberOfPassengers.sql | 46 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 NumberOfPassengers.sql

diff --git a/NumberOfPassengers.sql b/NumberOfPassengers.sql
new file mode 100644
index 0000000..5e1b81c
--- /dev/null
+++ b/NumberOfPassengers.sql
@@ -0,0 +1,46 @@
+-- Solution.1: 
+WITH CTE AS (
+    SELECT 
+        p.passenger_id, 
+        p.arrival_time, 
+        MIN(b.arrival_time) AS btime 
+    FROM 
+        passengers p 
+    INNER JOIN 
+        buses b 
+    ON 
+        p.arrival_time <= b.arrival_time 
+    GROUP BY 
+        p.passenger_id
+)
+SELECT 
+    b.bus_id, 
+    COUNT(c.btime) AS passengers_cnt 
+FROM 
+    buses b 
+LEFT JOIN 
+    CTE c 
+ON 
+    b.arrival_time = c.btime 
+GROUP BY 
+    b.bus_id 
+ORDER BY 
+    b.bus_id;
+
+-- Solution.2: 
+-- SELECT 
+--     b.bus_id, 
+--     COUNT(p.passenger_id) AS passengers_cnt
+-- FROM 
+--     Buses b
+-- LEFT JOIN 
+--     Passengers p ON p.arrival_time <= b.arrival_time
+-- AND NOT EXISTS (
+--     SELECT 1
+--     FROM Buses b2 
+--     WHERE b2.arrival_time < b.arrival_time AND p.arrival_time <= b2.arrival_time
+-- )
+-- GROUP BY 
+--     b.bus_id
+-- ORDER BY 
+--     b.bus_id;
\ No newline at end of file

From 9f8d320c28b60349c856c6cd6f86c08a6a90e148 Mon Sep 17 00:00:00 2001
From: Zaid Roshan Mayers <zaidmayers@gmail.com>
Date: Fri, 13 Dec 2024 21:56:24 -0500
Subject: [PATCH 2/3] Added solutions for UserActivity.sql

---
 UserActivity.sql | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 UserActivity.sql

diff --git a/UserActivity.sql b/UserActivity.sql
new file mode 100644
index 0000000..206d677
--- /dev/null
+++ b/UserActivity.sql
@@ -0,0 +1,33 @@
+-- Sol.1: 
+
+SELECT activity_date AS 'day', COUNT(DISTINCT user_id) AS 'active_users'
+FROM activity WHERE activity_date > '2019-06-27' AND activity_date <= '2019-07-27'
+GROUP BY 1;
+
+-- Sol.2:
+
+-- SELECT activity_date AS 'day', COUNT(DISTINCT user_id) AS 'active_users'
+-- FROM activity WHERE activity_date BETWEEN '2019-06-28' AND '2019-07-27'
+-- GROUP BY 1;
+
+-- Sol.3:
+
+-- SELECT activity_date AS 'day', COUNT(DISTINCT user_id) AS 'active_users'
+-- FROM activity WHERE DATEDIFF('2019-07-27', activity_date) >= 0 
+-- AND DATEDIFF('2019-07-27', activity_date) < 30
+-- GROUP BY 1;
+
+-- Sol.4: 
+
+-- SELECT activity_date AS 'day', COUNT(DISTINCT user_id) AS 'active_users'
+-- FROM activity WHERE activity_date BETWEEN DATE_SUB('2019-07-27', INTERVAL 29 DAY) 
+-- AND '2019-07-27'
+-- GROUP BY 1;
+
+
+-- Sol.5: 
+
+-- SELECT activity_date AS 'day', COUNT(DISTINCT user_id) AS 'active_users'
+-- FROM activity WHERE activity_date BETWEEN DATE_ADD('2019-07-27', INTERVAL -29 DAY) 
+-- AND '2019-07-27'
+-- GROUP BY 1;

From 80f243bae4a56588eaf4e3c697038ec1237d2719 Mon Sep 17 00:00:00 2001
From: Zaid Roshan Mayers <zaidmayers@gmail.com>
Date: Mon, 16 Dec 2024 19:50:16 -0800
Subject: [PATCH 3/3] Added solutions for ConsecutiveNumbers.sql

---
 ConsecutiveNumbers.sql | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 ConsecutiveNumbers.sql

diff --git a/ConsecutiveNumbers.sql b/ConsecutiveNumbers.sql
new file mode 100644
index 0000000..3c20649
--- /dev/null
+++ b/ConsecutiveNumbers.sql
@@ -0,0 +1,8 @@
+SELECT DISTINCT num AS ConsecutiveNums
+FROM (
+    SELECT num, 
+           LAG(num, 1) OVER (ORDER BY id) AS prev_num,
+           LEAD(num, 1) OVER (ORDER BY id) AS next_num
+    FROM Logs
+) as sub
+WHERE num = prev_num AND num = next_num;