Generate alphanumeric sequence with sql stored procedure - sql

Question

I need to Auto Generate Employee Reference number unique sequence with primary key. Sample Refno: (A0001-Z9999) now exeeded the maximum count(Z9999)
Next sequence I want to generate:
AA001-AA999,
AB001-AB999,
AZ999-BA001
BC001-BZ999,
CA001-CZ999,
ZA001-ZZ999..LIKE THIS..IN sql server stored procedure..
...ZZ999 LIKE THIS

Answer 1

This query will give you all values you need:
--here we take all the english alphabet
;WITH chars AS (
SELECT CHAR(65) as chars, 65 as [level]
UNION ALL
SELECT CHAR([level]+1), [level]+1
FROM chars
WHERE [level]-65 < 25
), cte AS ( -- Here we take didits from 1 to 999
SELECT 1 as digits
UNION ALL
SELECT digits+1
FROM cte
WHERE digits < 999
), codes AS ( -- here we get all chars combinations "AA", "AB" etc
SELECT c1.chars+c2.chars as code
FROM chars c1
cross join chars c2
)
--And here come cortesian join to get all refnomes ou need
SELECT code + CASE WHEN LEN(digits) = 1 THEN CONCAT('00',cast(digits as nvarchar(1)))
WHEN LEN(digits) = 2 THEN CONCAT('0',cast(digits as nvarchar(2)))
ELSE cast(digits as nvarchar(3)) END as Refno
FROM cte
CROSS JOIN codes
ORDER BY code
OPTION (maxrecursion 1000)
Output:
Refno
AA001
AA002
AA003
AA004
AA005
AA006
AA007
AA008
AA009
AA010
AA011
AA012
AA013
AA014
AA015
AA016
AA017
...
etc
ZZ999
~675324 rows
You can put the result into some table and in stored procedure return value you need from that table.

Answer 2

You can do it like this.
First create a SEQUENCE to generate integer sequence numbers starting from 1.
CREATE SEQUENCE dbo.MySeq AS INT
START WITH 1
INCREMENT BY 1;
Then create a stored procedure which generates a sequence code in the required format.
CREATE PROCEDURE dbo.up_GetNextSequence
(
#seq nchar(5) out
)
AS
DECLARE #i int = NEXT VALUE FOR dbo.MySeq;
IF #i > 685323
BEGIN
RAISERROR(N'Sequence is out of range.', 16, 0);
END
IF #i < 10000
BEGIN
SET #seq = N'A' + FORMAT(#i, 'D4');
END
ELSE
BEGIN
DECLARE #j int;
SET #j = #i - 9999;
DECLARE #k int;
SET #k = ((#j - 1) % 999) + 1;
DECLARE #l int;
SET #l = (#j - 1) / 999;
DECLARE #m int;
SET #m = (#l % 26) + 65;
DECLARE #n int;
SET #n = (#l / 26) + 65;
SET #seq = NCHAR(#n) + NCHAR(#m) + FORMAT(#k, 'D3');
END;
Then test the stored procedure.
DECLARE #seq nchar(5);
EXEC up_GetNextSequence #seq output;
SELECT #seq AS '#seq'
Call it four more times and we get to "A0005".
To test the first breakpoint, alter the sequence object so that it returns 9999. Then execute the test code again.
ALTER SEQUENCE dbo.MySeq
RESTART WITH 9999;
And so on...
ALTER SEQUENCE dbo.MySeq
RESTART WITH 10998;
ALTER SEQUENCE dbo.MySeq
RESTART WITH 35973;
ALTER SEQUENCE dbo.MySeq
RESTART WITH 659349;
To test what happens when it gets to the end of the allowed range.
ALTER SEQUENCE dbo.MySeq
RESTART WITH 685323;
Execute the stored procedure one more time and it raises an error, saying the sequence is out of range. This is by design.