Complex SQL Select Query - sql

Question

Table schema:
CREATE TABLE TRANSACTIONDETAILS
(
TransNo CHAR(15),
Serial INT,
Project CHAR(3)
)
Dataset:
+-----------------+--------+---------+
| TransNo | Serial | Project |
+-----------------+--------+---------+
| A00000000000001 | 1 | 100 |
| A00000000000001 | 2 | 101 |
| A00000000000002 | 1 | 100 |
| A00000000000002 | 2 | 101 |
| A00000000000003 | 1 | 100 |
| A00000000000003 | 2 | 200 |
| A00000000000004 | 1 | 200 |
| A00000000000004 | 2 | 100 |
| A00000000000005 | 1 | 101 |
| A00000000000005 | 2 | 100 |
+-----------------+--------+---------+
I want to identify transactions those have same project sets.
Expected output:
+-----------------+--------+---------+---------+
| TransNo | Serial | Project | Flag |
+-----------------+--------+---------+---------+
| A00000000000001 | 1 | 100 | 1 |
| A00000000000001 | 2 | 101 | 1 |
| A00000000000002 | 1 | 100 | 1 |
| A00000000000002 | 2 | 101 | 1 |
| A00000000000005 | 1 | 101 | 1 |
| A00000000000005 | 2 | 100 | 1 |
| A00000000000003 | 1 | 100 | 2 |
| A00000000000003 | 2 | 200 | 2 |
| A00000000000004 | 1 | 200 | 2 |
| A00000000000004 | 2 | 100 | 2 |
+-----------------+--------+---------+---------+
I am using SQL Server 2012 and later.
Thanks.
UPDATE 1: Partially my objective would be achieved if I make following from input dataset.
+-----------------+---------+---------+
| TransNo | Project1| Project2|
+-----------------+---------+---------+
| A00000000000001 | 100 | 101 |
| A00000000000002 | 100 | 101 |
| A00000000000003 | 100 | 200 |
| A00000000000004 | 200 | 100 |
| A00000000000005 | 101 | 100 |
+-----------------+---------+---------+
UPDATE 2:
Data set
+-----------------+--------+---------+
| TransNo | Serial | Project |
+-----------------+--------+---------+
| A00000000000001 | 1 | 100 |
| A00000000000001 | 2 | 101 |
| A00000000000001 | 3 | 200 |
| A00000000000002 | 1 | 100 |
| A00000000000002 | 2 | 101 |
| A00000000000003 | 1 | 100 |
| A00000000000003 | 2 | 200 |
| A00000000000004 | 1 | 200 |
| A00000000000004 | 2 | 100 |
| A00000000000005 | 1 | 101 |
| A00000000000005 | 2 | 100 |
+-----------------+--------+---------+
Output:
+-----------------+--------+---------+---------+
| TransNo | Serial | Project | Flag |
+-----------------+--------+---------+---------+
| A00000000000001 | 1 | 100 | 1 |
| A00000000000001 | 2 | 101 | 1 |
| A00000000000001 | 2 | 200 | 1 |
| A00000000000002 | 1 | 100 | 2 |
| A00000000000002 | 2 | 101 | 2 |
| A00000000000005 | 1 | 101 | 2 |
| A00000000000005 | 2 | 100 | 2 |
| A00000000000003 | 1 | 100 | 3 |
| A00000000000003 | 2 | 200 | 3 |
| A00000000000004 | 1 | 200 | 3 |
| A00000000000004 | 2 | 100 | 3 |
+-----------------+--------+---------+---------+

Answer 1

Try this
;WITH cte
AS (SELECT *,
Concat(Min(Project)OVER(partition BY TransNo), Max(Project)OVER(partition BY TransNo)) AS inter
FROM TRANSACTIONDETAILS)
SELECT TransNo,
Serial,
Project,
Dense_rank()OVER(ORDER BY inter) AS flag
FROM cte
SQL FIDDLE DEMO
Update : For partial result
SELECT TransNo,
Max(CASE WHEN Serial = 1 THEN Project END) AS Project_1,
Max(CASE WHEN Serial = 2 THEN Project END) AS Project_2
FROM TRANSACTIONDETAILS
GROUP BY TransNo

Answer 2

CREATE TABLE #test_trans
([TransNo] varchar(15), [Serial] int, [Project] int)
;
INSERT INTO #test_trans
([TransNo], [Serial], [Project])
VALUES
('A00000000000001', 1, 100),
('A00000000000001', 2, 101),
('A00000000000001', 3, 200),
('A00000000000002', 1, 100),
('A00000000000002', 2, 101),
('A00000000000003', 1, 100),
('A00000000000003', 2, 200),
('A00000000000004', 1, 200),
('A00000000000004', 2, 100),
('A00000000000005', 1, 101),
('A00000000000005', 2, 100)
;
[![;WITH cte
AS (select \[TransNo\],(
Select cast(ST1.\[Project\] as varchar(max)) AS \[text()\]
From #test_trans ST1
where st1.TransNo=st2.TransNo
For XML PATH ('')) as rn,Project,st2.Serial from #test_trans st2)
SELECT TransNo,
Serial,
Project,
Dense_rank()OVER(ORDER BY rn) AS flag
FROM cte][1]][1]