SQL - Case when lineid='01' then newid else id

Question

I have this kind of data in my table

lineid	price €
01	100.00
02	200.00
01	10.34
01	311.12
01	14.33
02	36.44
03	89.70
04	11.33

and i would like my output to be like this

docid	lineid	price €
1	01	100
1	02	200.00
2	01	10.34
3	01	311.12
4	01	14.33
4	02	36.44
4	03	89.70
4	04	11.33

Its data for invoices and for every line that has lineid='01' it means that the info is for different invoice so i have to mark it with new documentID that i want you to help me create it with a command.

Its probably something easy but i am searching like a maniac here and i cant find the solution.

EDIT: Yes , it Is "increment docid each time lineid equals 01" what i want

Answer 1

You could use running counts using something like below (assuming this is MS SQL you are talking about)

SELECT ROW_NUMBER() over(partition by [LineId] order by [LineId]) as DocId,
      [LineId],
      [Price]
  FROM [StackOverflow].[dbo].[RunningCount] order by [LineId]