Get rows by id list keeping the order

[Carlos Cesar Caballero Díaz]

Hi guys, I have a list of ids, and I need to obtain the records keeping
the list order. In MySQL I can use FIELD() in the "order by" for that.
Can I get the ordered records using the DAL?

Greetings.

[Anthony]

The DAL doesn't have anything built in that will work across database backends, but if you are using MySQL, you should be able to do:

db(query).select(orderby='Field(id, %s)' % ', '.join(str(id) for id in list_of_ids))

Alternatively, if the list is not too long, you can just do the sorting in Python after selection:

db(query).select().sort(lambda r: list_of_ids.index(r.id))

Anthony

[Carlos Cesar Caballero Díaz]

Thanks Anthony, I will go with the first option and guess how to adapt it to postgress too.

Greetings.

El 22/04/18 a las 12:12, Anthony escribió:

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[Leonel Câmara]

I would make a function that automatically generated case statements for the orderby

def make_orderby(idlist):
    result="CASE"
    for i, el in enumerate(idlist):
        result += " WHEN id = %d THEN '%d' " % (el, i)
    result += " ELSE id END ASC"
    return result  

I have not tested this...

[Carlos Cesar Caballero Díaz]

Thanks Leonel, that sounds interesting, I will take a look.

Greetings.

El 23/04/18 a las 11:30, Leonel Câmara escribió: