Repeating rows based on the frequency - sql

Question

I have a table with 2 columns named A and B which is defined as :
A B
c1 2
c2 3
c3 4
The expected output is :
A B
c1 1
c1 2
c2 1
c2 2
c2 3
c3 1
c3 2
c3 3
c3 4

Answer 1

CREATE TABLE #table2
([A] varchar(2), [B] int)
;
INSERT INTO #table2
([A], [B])
VALUES
('c1', 2),
('c2', 3),
('c3', 4)
;WITH nums AS
(SELECT 1 AS value ,a,b from #table2
UNION ALL
SELECT value + 1 AS value ,A,b
FROM nums
WHERE nums.value <B)
SELECT a,value
FROM nums order by a,value
output
a value
c1 1
c1 2
c2 1
c2 2
c2 3
c3 1
c3 2
c3 3
c3 4

Answer 2

Created a Table valued function in which i used Recursive cte to evaluate recurring value of given in put Then Join the table with function using Cross Apply
CREATE FUNCTION [dbo].[udf_GetData] (
#Data INT
)
RETURNS #output TABLE (
Data INT
)
BEGIN
;WITH CTe
AS
(
SELECT 1 As Data
UNION ALL
SELECT Data+1
FROM CTe
WHERE Data < #Data
)
INSERT INTO #output
SELECT Data FROM CTe
RETURN
END
Sample Data and explained How to call function using CROSS APPLY
DECLARE #Data AS TABLE (A VARCHAR(10),B INT)
INSERT INTO #Data
SELECT 'c1', 2 UNION ALL
SELECT 'c2', 3 UNION ALL
SELECT 'c3', 4
SELECT d.A,
(SELECT [dbo].[udf_GetData](d.B)) AS RecData
FROM #Data d
Result
A RecursiveData
----------------
c1 1
c1 2
c2 1
c2 2
c2 3
c3 1
c3 2
c3 3
c3 4

Answer 3

You could try this:
// test data
declare #tbl table(A char(2), B int);
insert into #tbl values
('c1', 2),
('c2', 3),
('c3', 4);
// create CTE with numbers which we will need to join
declare #max int;
select #max = max(B) from #tbl;
;with numbers as (
select 1 n
union all
select n + 1 from numbers
where n < #max
)
// join numbers with your table
select A, n from #tbl t
join numbers n on t.B >= n.n
order by A, n

Answer 4

Say, your table name is test.
WITH r(a, b, repeat) as
(SELECT a, b, 1 from test
union all
select a, b, repeat+1 from r
where r.repeat < r.b)
select * from r
ORDER BY a, repeat;