dense_rank() function equivalent in access database - sql

Question

As we have dense_rank function in sql server do we any equivalent in access?
I have a table
employee_name employee_address
RON 23-B, TORONTO
PETER 15-C, NY
TED 23-C, LONDON
RON 23-B, TORONTO
I have to add new column to this table as follows:
employee_name employee_address employee_no
RON 23-B, TORONTO 1
PETER 15-C, NY 2
TED 23-C, LONDON 3
RON 23-B, TORONTO 1

Answer 1

I assume you want to port in Access a SQL Server query like this:
SELECT *
,DENSE_RANK() OVER(ORDER BY employee_name, employee_address) AS DenseRank
FROM Employee.
The main idea is to generate a list with distinct employee_name & employee_address values and then we generate row numbers without gaps for every distinct tuple. At final step, we make a JOIN between the initial data set (Employee table) and the last data set (which has row numbers for every distinct employee_name & employee_address tuple).
Solution 1
Query0
CREATE TABLE Employee
(
employee_id INT PRIMARY KEY
,employee_name VARCHAR(100) NOT NULL
,employee_address VARCHAR(100) NOT NULL
);
Query1
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (1,'RON','23-B, TORONTO');
Query2
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (2,'PETER','15-C, NY');
Query3
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (3,'TED','23-C, LONDON');
Query4
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (4,'SORIN','09-S, VASCAUTI');
Query5
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (5,'RON','23-B, TORONTO');
Query6
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (6,'PETER','15-C, NY');
Query7
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (7,'SORIN','09-S, VASCAUTI');
Query8
INSERT INTO Employee (employee_id, employee_name, employee_address)
VALUES (8,'PETER','15-C, NY');
So, the Employee content will be:
employee_id employee_name employee_address
----------- ---------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------
1 RON 23-B, TORONTO
2 PETER 15-C, NY
3 TED 23-C, LONDON
4 SORIN 09-S, VASCAUTI
5 RON 23-B, TORONTO
6 PETER 15-C, NY
7 SORIN 09-S, VASCAUTI
8 PETER 15-C, NY
Query9 We generate row numbers for every employee_name & employee_address tuple
CREATE TABLE TmpEmployee
(
rownumber COUNTER(1,1) PRIMARY KEY
,employee_name VARCHAR(100) NOT NULL
,employee_address VARCHAR(100) NOT NULL
);
(COUNTER(1,1) is Access/SQL AutoNumber data type; before every Query10 execution you need to recreate TmpEmployee table or you need to compact Access DB to reset rownumber counter to 1) and
Query10
INSERT INTO TmpEmployee (employee_name, employee_address)
SELECT e.employee_name, e.employee_address
FROM Employee e
GROUP BY e.employee_name, e.employee_address
Results:
rownumber employee_name employee_address
----------- ---------------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------------------
1 PETER 15-C, NY
2 RON 23-B, TORONTO
3 SORIN 09-S, VASCAUTI
4 TED 23-C, LONDON
Query11 The final results:
SELECT e.*, t.RowNumber AS DenseRank
FROM Employee e
INNER JOIN TmpEmployee t ON e.employee_name = t.employee_name AND e.employee_address = t.employee_address
ORDER BY e.employee_name, e.employee_address
Results:
2 PETER 15-C, NY 1
6 PETER 15-C, NY 1
8 PETER 15-C, NY 1
5 RON 23-B, TORONTO 2
1 RON 23-B, TORONTO 2
4 SORIN 09-S, VASCAUTI 3
7 SORIN 09-S, VASCAUTI 3
3 TED 23-C, LONDON 4
Solution 2
Query9 The final results:
SELECT e.*, c.RowNumber
FROM Employee e INNER JOIN
(
SELECT a.employee_name, a.employee_address, COUNT(b.employee_name) AS RowNumber
FROM
(
SELECT e.employee_name, e.employee_address
FROM Employee e
GROUP BY e.employee_name, e.employee_address
) a,
(
SELECT e.employee_name, e.employee_address
FROM Employee e
GROUP BY e.employee_name, e.employee_address
) b
WHERE a.employee_name > b.employee_name OR a.employee_name = b.employee_name AND a.employee_address >= b.employee_address
GROUP BY a.employee_name, a.employee_address
) c ON e.employee_name = c.employee_name AND e.employee_address = c.employee_address
ORDER BY c.employee_name, c.employee_address