行的顺序编号

Question

I have to customize a SQL view to be able to perform a system integration test. One table keeps track of the transactions and the LINE ITEMS per transactions (for example, transaction 2 has three items, so there are three consecutive rows corresponding to the same transaction number) What I need to accomplish is to get a column where I keep track of the number of items for THAT transaction, always starting from 1 for each transaction.

For example, the first column is TransactionNumber and the second is DesiredOutput :

1                    1
1                    2
2                    1
2                    2
2                    3
3                    1
4                    1
4                    2

ETC...

I know how to number consecutive rows on the WHOLE table, but I cannot find any reference to this numbering that depends on a value on another row.

Answer 1

For SQL Server 2005+ and Oracle you can use the following:

SELECT TransNumber, ROW_NUMBER() OVER(PARTITION BY Transnumber ORDER BY Something) [DESIRED COLUMN OUTPUT]
FROM YourTable