Implementation of Rank and Dense Rank in MySQL - mysql

Question

Hi I am a Begineer in MySql and I want to Implement Rank and Dense Rank Function on MySql for the given problem statement stated below.
I have a Table called Transaction which has following Columns:
Transaction_no | Register|Adult|child
The Input Data is as follows:
INPUT
+----------------+----------+-------+-------+
| transaction_no | register | adult | child |
+----------------+----------+-------+-------+
| 1234 | A | 0 | 1 |
| 1234 | A | 1 | 2 |
| 1234 | A | 1 | 1 |
| 3456 | B | 1 | 0 |
| 5678 | B | 1 | 0 |
| 2468 | C | 1 | 0 |
| 2468 | C | 0 | 1 |
+----------------+----------+-------+-------+
My Requirement is to add another column namely rn using mySQL which will use Rank and dense rank like logic to generate the following intermediate output
INTERMEDIATE
+----------------+----------+-------+-------+----+
| transaction_no | register | adult | child | rn |
+----------------+----------+-------+-------+----+
| 1234 | A | 0 | 1 | 1 |
| 1234 | A | 1 | 2 | 2 |
| 1234 | A | 1 | 1 | 3 |
| 3456 | B | 1 | 0 | 1 |
| 5678 | B | 1 | 0 | 1 |
| 2468 | C | 1 | 0 | 1 |
| 2468 | C | 0 | 1 | 2 |
+----------------+----------+-------+-------+----+
Here the partition is done on transaction number.
The Final Query Output should contain all the rows whose rn=1 and the rn value should not displayed.
OUTPUT
+----------------+----------+-------+-------+
| transaction_no | register | adult | child |
+----------------+----------+-------+-------+
| 1234 | A | 0 | 1 |
| 3456 | B | 1 | 0 |
| 5678 | B | 1 | 0 |
| 2468 | C | 1 | 0 |
+----------------+----------+-------+-------+
Oracle Documentation for Reference : OracleDocument
I have also added SQL fiddle for Reference.SqlFiddle
Please help me on this.

Answer 1

MySQL Solution:
SELECT transaction_no, register, adult, child
FROM (
SELECT
( CASE WHEN #prev_tno != transaction_no THEN #rn:=1
ELSE #rn:=(#rn+1) END ) AS rn
, #prev_tno:=transaction_no AS transaction_no
, register, adult, child
FROM instructor
, (SELECT #rn:=0, #prev_tno:=NULL) AS row_nums
) src
WHERE rn = 1
ORDER BY register, transaction_no
Note: Desired ordering can only be achieved on explicit request, hence ORDER BY is used in the query.

Answer 2

declare #t table (TransactionId int,register VARCHAR(1),Adult INT,Child INT )
insert into #t (TransactionId,register,Adult,Child)values (1234,'A',0,1),
(1234,'A',1,2),(1234,'A',1,1),(3456,'B',1,0),(5678,'B',1,0),(2468,'C',1,0),(2468,'C',0,1)
;with cte as (
select TransactionId,register,Adult,Child,ROW_NUMBER()OVER(PARTITION BY TransactionId,register ORDER BY register ) RN from #t
)
Select TransactionId,register,Adult,Child from cte where RN = 1

Answer 3

create table TRANSACTION
(
Transaction_no int,
Register varchar2(2),
Adult int,
child int
);
Insert rows in TRANSACTION table.
Sqlquery for Intermediate output:-
select TRANSACTION_NO,REGISTER,Adult,child, DENSE_RANK() over(PARTITION BY REGISTER ORDER BY Adult,child) as rnk from TRANSACTION;
Sqlquery for Final output:-
select TRANSACTION_NO,REGISTER,Adult,child from (
select TRANSACTION_NO,REGISTER,Adult,child, DENSE_RANK() over(PARTITION BY TRANSACTION_NO ORDER BY Adult,child) as rnk from TRANSACTION)
where rnk=1;
I tried it on Oracle.