Re: Help on SQL query
От | Rob Sargent |
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Тема | Re: Help on SQL query |
Дата | |
Msg-id | 499C11DB-F3CF-4316-845A-19ABCAF52962@gmail.com обсуждение исходный текст |
Ответ на | Re: Help on SQL query (Andrew Gierth <andrew@tao11.riddles.org.uk>) |
Ответы |
Re: Help on SQL query
|
Список | pgsql-sql |
> On Feb 15, 2019, at 10:28 AM, Andrew Gierth <andrew@tao11.riddles.org.uk> wrote: > >>>>>> "Ian" == Ian Tan <iantan1268@gmail.com> writes: > > Ian> How do I write an SQL query so that the "name" text in car_parts > Ian> are added to the bill_of_materials table, so that it looks like > Ian> this: > > The only trick with this is that you need to join the car_parts table > twice (once for parent and once for child), and to do that you need to > give it different alias names: > > select bom.parent_id, > ppart.name as parent_name, > bom.child_id, > cpart.name as child_name > from bill_of_materials bom > join car_parts ppart on (ppart.id=bom.parent_id) > join car_parts cpart on (cpart.id=bom.child_id); > > -- > Andrew (irc:RhodiumToad) > Andrew, will you do my homework too?
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