Km beregner

Try something like this

SELECT DF.ID, DF.KM, [KM]-(SELECT  max(KM) from dieselforbrug where dieselforbrug.ID < DF.ID) AS [KM Kørt]
FROM Dieselforbrug AS DF

Not a good idea to use ID-1 because there is no guaranty the previous record will have an id which is one less

In my example I only have one column with KM for each ID and it calculates Km kørt since previous ID

Hej.
Tak for svaret. Men jeg får en fejl: Syntaks til underforespørgsel er forkert. Kontroller syntaksen og omslut underforespørgsler med paranteser. men jeg kan ikke lige se hvor den mangler.

Hvis ikke id rækkefølgen passer, som den måske ikke altid gør, er det så den korrekte SQL?

"er det så den korrekte SQL? "
My SQL or your SQL?

That all depends on what you want, so if you give an example of your data and of what you expect in result it will be easier to say.

I'm guessing that you are actually inserting Dieselforbrug.[Km kørt] so no need to calculate it.

So

SELECT DF.ID, DF.Dato, DF.KM, (SELECT  max(KM) from dieselforbrug where dieselforbrug.ID < DF.ID) AS [Previous KM]
FROM Dieselforbrug AS DF

will probably give the result I think you are trying to get from your sql

In the sql I gave first

"SELECT DF.ID, DF.KM, [KM]-(SELECT  max(KM) from dieselforbrug where dieselforbrug.ID < DF.ID) AS [KM Kørt]
FROM Dieselforbrug AS DF"

I have a table named dieselforbrug with two fields only. ID and KM and it works here, so I assume your sql is wrong

you are also welcome to send an example of the dB and I'll take a look
ekspertenATsanthell.dk

AT = @

Hej igen.Tak for svaret.
Ja det er korrekt, jeg indsætter sql'en i næste ledige kolonne i forespørgslen i første felt. der er følgende kolloner: id, Dato, KM, og endelig den tomme kolonne hvor jeg sætter sql'en ind. Den bør vel starte med:
Kørt KM: SELECT DF.ID, DF.Dato, DF.KM, (SELECT  max(KM) from dieselforbrug where dieselforbrug.ID < DF.ID) AS [Previous KM]
FROM Dieselforbrug AS DF

Men når jeg sætter sql ind får jeg stadig fejlen: Syntaksen til underforespørgsel er forkert. Kontroller syntaksen og omslut underforespørgsler med paranteser.

:-)

OK, the sql is NOT for a single column but to replace the sql in your query.

If you are trying to calculate "Kørt KM" then use the first sql I gave, it has to replace you sql not just in one column.

Jeg har sendt dig DB. er det ud fra den du giver svaret?

"er det ud fra den du giver svaret? "?

Har modtaget dB...

I have sent dB to you, hope its what you are after.

Thanks. I have placed a comment in your new question.