Provide a Built-in Function for Sequential Row Numbers in Query Output

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Description:

SQL Server should introduce a robust built-in function to generate a sequential row number for any query output, without requiring an explicit ORDER BY or window functions like ROW_NUMBER().

Currently, SQL Server users often rely on:

1. ROW_NUMBER() OVER (ORDER BY (SELECT 1)) – which is not always stable due to execution plan optimizations and parallelism.
2. Manually assigning row numbers in loops – which is inefficient for large datasets.
3. SSMS automatically assigning row numbers in result sets – but this behavior is unavailable in T-SQL queries.

Proposed Solution:
Introduce a built-in, lightweight function like:

SELECT SEQ_NUMBER(), * FROM MyQuery;

Where SEQ_NUMBER() assigns a sequential number based on the final result set order, similar to how SSMS automatically numbers rows in its output.

Benefits:
✅ Works without needing an explicit ORDER BY.
✅ Eliminates reliance on ROW_NUMBER() OVER (ORDER BY (SELECT 1)), which can be unstable in parallel execution.
✅ Reduces unnecessary sorting overhead when users only need a sequence number.
✅ Aligns with SSMS behaviour, where query results are always displayed with row numbers.

This feature would greatly simplify reporting queries, temporary data processing, and procedural workflows where a sequence is needed without an ordering constraint.

Example Use Case:
SELECT SEQ_NUMBER(), CustomerName, OrderAmount
FROM Orders
WHERE OrderDate > '2024-01-01';

Expected Output:

SEQ_NUMBER() | CustomerName | OrderAmount

1 | John Doe | 500.00
2 | Jane Smith | 700.00
3 | Mike Ross | 300.00

Would love to hear thoughts from the SQL Server team and the community on this!

Jagdish M