Whats the most efficient query for this result?

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От Nick
Тема Whats the most efficient query for this result?
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Msg-id 7ebf0924-621d-4c27-a987-bb73df71f4be@l17g2000yqb.googlegroups.com
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Ответы Re: Whats the most efficient query for this result?  (Tom Molesworth <tom@audioboundary.com>)
Список pgsql-general
I have three tables (users, books, pencils) and would like to get a
list of all users with a count and total price of their books and
pencils for 2012-01-01...

So with this data...

users (user_id)
1
2
3

books (user_id, price, created)
1 | $10 | 2012-01-01
1 | $10 | 2012-01-01
3 | $10 | 2012-01-01

pencils
1 | $.50 | 2012-01-02
3 | $.50 | 2012-01-01
3 | $.50 | 2012-01-02

What is the most efficient way to get this result...

query_result (user_id, book_count, book_price_total, pencil_count,
pencil_price_total)
1 | 2 | $20 | 0 | $0
2 | 0 | $0 | 0 | $0
3 | 1 | $10 | 1 | $.50


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