st: detecting repeated observations

[Estrella Gomez <estrellastata@gmail.com>]

Hi,

I am working with a database that contains music records. I would like
to detect observations in which the title is the same title but the
artist is different; for instance, "The power of love" is a song from
Celine Dion, but also from Huey Lewis & the News. I have tried this
command:

list if title==title & artist!=artist

but reports nothing.

In addition, I would like to find observations with the same title but
different identifier; however,

list if title==title & id!=id

again reports nothing

Any idea?

Thanks,
Estrella
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