"Array" usage in T-SQL - sql

Question

Trying to create a temp table where the AlphaSeq column would go through an "array" of alphanumeric characters that do not repeat and follow a flow as shown in the example below.
Example:
AlphaSeq
NumericSeq
A
1
A1
2
B
3
B1
4
AA
5
AB
6
BA
7
BB
8
[ETC]
[ETC]
Here's what I have so far (Obviously the "IG" is static as it is written now, so Im trying to make that field more fluid)
CREATE TABLE #Index
(
AlphaSeq VARCHAR(2),
NumericSeq TINYINT
)
DECLARE #ArrayNum AS TINYINT;
DECLARE #ReceiptSeq AS VARCHAR(2);
SET #ArrayNum = 0
SET #ReceiptSeq = 'IG'
WHILE #ArrayNum < 100
BEGIN
SET #ArrayNum = #ArrayNum + 1
INSERT INTO #Index (AlphaSeq, NumericSeq)
VALUES (#ReceiptSeq, #ArrayNum)
END
SELECT *
FROM #Index

Answer 1

You can simply cross-join the list of characters
CREATE TABLE #Index
(
AlphaSeq VARCHAR(2) NOT NULL,
NumericSeq SMALLINT NOT NULL IDENTITY
);
WITH Chars AS (
SELECT *
FROM (VALUES
('A'),('B'),('C'),('D'),('E'),('F'),('G'),('H'),('I'),('J'),('K'),('L'),('M'),('N'),('O'),('P'),('Q'),('R'),('S'),('T'),('U'),('V'),('W'),('X'),('Y'),('Z')
) v(chr)
),
CharsWithNums AS (
SELECT *
FROM (VALUES
('1'),('2'),('3'),('4'),('5'),('6'),('7'),('8'),('9'),('0')
) v(chr)
UNION ALL
SELECT *
FROM Chars
)
INSERT #Index (AlphaSeq)
SELECT chr AS AlphaSeq
FROM Chars
UNION ALL
SELECT a.chr + b.chr
FROM Chars a
CROSS JOIN CharsWithNums b
ORDER BY AlphaSeq;