How to Append Rows and Sequentially Number Them in SQL Based on a Count?

Appending Rows and Numbering Results in SQL

How can I expand a result set to include multiple rows for each row with a count greater than 1, while numbering them sequentially? For instance, consider the following table with values and counts:

Value	Count
foo	1
bar	3
baz	2

Our desired output would be:

Value	Count	Index
foo	1	1
bar	3	1
bar	3	2
bar	3	3
baz	2	1
baz	2	2

To achieve this cross-database compatibility, consider using a "Numbers" table:

SELECT value, count, number
FROM table
JOIN Numbers
ON table.count >= Numbers.number

This solution generates a sequence of numbers up to the maximum count in the table. By joining the original table with the Numbers table, we effectively repeat rows and assign sequential indices. Here is an example using Microsoft SQL Server:

WITH Numbers AS (
    SELECT ROW_NUMBER() OVER (ORDER BY number) AS number
    FROM (
        SELECT 1 AS number
        UNION ALL
        SELECT number + 1
        FROM Numbers
        WHERE number < (MAX(count) OVER ())
    ) AS Outer
)
SELECT value, count, number
FROM table
JOIN Numbers
ON table.count >= Numbers.number

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