Re: simple update from select ??

On Monday 07 March 2005 12:28 pm, you wrote:
> Hi folks
>
> I've got a table of pieces of equipment.
> One piece of equipment may be owned by another piece of equipment,
> and may own multiple other pieces.
>
> To hold the relationship I have a piece_pieces table holding the
> owner (pp_id) part id and the owned part ids (pp_part).
>
> I'v realised I can store this within the original table so I've added
> an owner attribute. I need to now populate this now from the other
> table, but I can't work out how.
>
> I've got pieces table
>
> p_id -- part id
> p_owner -- new owner attribute
>
> piece_pieces table
>
> pp_id -- id of owner
> pp_part -- id of owned

For my own future reference as much as anything, here's the required
statement, which is a syntactically corrected version of a suggestion
by Sean Davis

update pieces set p_owner=piece_pieces.pp_id from piece_pieces where
piece_pieces.pp_part=pieces.p_id;

Under Sean's suggestion I did this inside a transaction block so I could
check that it did what I wanted.
--
Gary Stainburn

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