From 03ad4486bb56fe230201b12661faf13a016e4f5d Mon Sep 17 00:00:00 2001
From: tejas274 <shahtejas274@gmail.com>
Date: Wed, 21 May 2025 09:21:53 -0400
Subject: [PATCH 1/4] feat: sql 2 problem 1 and problem 2

---
 problem-1.sql |  5 +++++
 problem-2.sql | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 problem-1.sql
 create mode 100644 problem-2.sql

diff --git a/problem-1.sql b/problem-1.sql
new file mode 100644
index 0000000..7c6c8d6
--- /dev/null
+++ b/problem-1.sql
@@ -0,0 +1,5 @@
+select
+score,
+dense_rank() over(order by score desc) AS `rank`
+from
+Scores
\ No newline at end of file
diff --git a/problem-2.sql b/problem-2.sql
new file mode 100644
index 0000000..5fd3ddf
--- /dev/null
+++ b/problem-2.sql
@@ -0,0 +1,35 @@
+--case statement
+select
+     case
+        when id%2=1 and id < (select max(id) from seat) then id + 1
+        when id%2=0 then id-1
+     else
+        id
+    END AS id,
+    student
+from
+    seat
+order by id
+
+--self join
+SELECT
+  s1.id,
+  COALESCE(s2.student, s1.student) AS student
+FROM Seat s1
+LEFT JOIN Seat s2
+  ON (
+    (s1.id % 2 = 1 AND s2.id = s1.id + 1) OR
+    (s1.id % 2 = 0 AND s2.id = s1.id - 1)
+  )
+ORDER BY s1.id;
+
+--window function lead,lag
+SELECT
+  id,
+  case
+     when id%2=1 and id < (select max(id) from seat) then lead(student) over(order by id)
+     when id%2=0 then lag(student) over(order by id)
+     else student
+   END as student
+FROM Seat
+ORDER BY id

From 23994741848019691935eb78d07bcac24eb24ba2 Mon Sep 17 00:00:00 2001
From: tejas274 <shahtejas274@gmail.com>
Date: Wed, 21 May 2025 09:27:58 -0400
Subject: [PATCH 2/4] correcting names of files for future ref

---
 problem-1.sql => problem1-178-rank-scores.sql    | 0
 problem-2.sql => problem2-626-exchange-seats.sql | 0
 2 files changed, 0 insertions(+), 0 deletions(-)
 rename problem-1.sql => problem1-178-rank-scores.sql (100%)
 rename problem-2.sql => problem2-626-exchange-seats.sql (100%)

diff --git a/problem-1.sql b/problem1-178-rank-scores.sql
similarity index 100%
rename from problem-1.sql
rename to problem1-178-rank-scores.sql
diff --git a/problem-2.sql b/problem2-626-exchange-seats.sql
similarity index 100%
rename from problem-2.sql
rename to problem2-626-exchange-seats.sql

From 31d59226afc8b78e51e2dfb678b8693c65da3b42 Mon Sep 17 00:00:00 2001
From: tejas274 <shahtejas274@gmail.com>
Date: Thu, 22 May 2025 08:38:25 -0400
Subject: [PATCH 3/4] feat: sql-2 added different way

---
 problem2-626-exchange-seats.sql | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/problem2-626-exchange-seats.sql b/problem2-626-exchange-seats.sql
index 5fd3ddf..e6a635c 100644
--- a/problem2-626-exchange-seats.sql
+++ b/problem2-626-exchange-seats.sql
@@ -33,3 +33,12 @@ SELECT
    END as student
 FROM Seat
 ORDER BY id
+
+--bitwise operator
+SELECT
+  s1.id,
+  coalesce(s2.student,s1.student) as student
+FROM Seat s1
+left join Seat s2
+on (s1.id +1)^1-1=s2.id
+ORDER BY id

From f08f96cd374329c2590c1e37b1805d7a69b8e9a4 Mon Sep 17 00:00:00 2001
From: tejas274 <shahtejas274@gmail.com>
Date: Fri, 23 May 2025 09:02:27 -0400
Subject: [PATCH 4/4] feat: problem 3 solution added

---
 problem3-608-tree-nodes.sql | 39 +++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 problem3-608-tree-nodes.sql

diff --git a/problem3-608-tree-nodes.sql b/problem3-608-tree-nodes.sql
new file mode 100644
index 0000000..2028b1b
--- /dev/null
+++ b/problem3-608-tree-nodes.sql
@@ -0,0 +1,39 @@
+--case statement
+SELECT
+    id,
+    CASE
+        WHEN p_id IS NULL THEN 'Root'
+        WHEN id NOT IN (SELECT DISTINCT p_id FROM Tree WHERE p_id IS NOT NULL) then 'Leaf'
+        ELSE 'Inner'
+    END AS type
+FROM Tree;
+
+--if condition
+SELECT
+    id,
+    IF(P_id is null,'Root',IF(id not in (select distinct p_id from Tree where p_id is not null),'Leaf','Inner')) AS type
+FROM Tree;
+
+--union
+
+SELECT
+    id,
+    'Root' AS type
+FROM Tree
+where p_id is null
+
+union
+
+SELECT
+    id,
+    'Leaf' AS type
+FROM Tree
+where id not in (select distinct p_id from Tree where p_id is not null) and p_id is not null
+
+union
+
+SELECT
+    id,
+    'Inner' AS type
+FROM Tree
+where id in (select distinct p_id from Tree) and p_id is not null
\ No newline at end of file