Rewritten queries

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От Keith Worthington
Тема Rewritten queries
Дата
Msg-id 20041227184511.M18423@narrowpathinc.com
обсуждение исходный текст
Ответы Re: Rewritten queries  (Jaime Casanova <systemguards@yahoo.com>)
Re: Rewritten queries  (Jaime Casanova <systemguards@yahoo.com>)
Список pgsql-novice
Hi All,

I wrote a query that created a view and when I looked at it in the database
the SELECT statement was very different.  In part

SELECT items.id,
       COALESCE(sales.sum, 0) AS committed,
       COALESCE(purchases.sum, 0) AS on_order,
       COALESCE(stock.quantity, 0) AS on_hand
  FROM peachtree.tbl_item AS items...

was changed to

CREATE OR REPLACE VIEW interface.view_inventory AS

 SELECT items.id,
        CASE
            WHEN (sales.sum IS NOT NULL ) THEN sales.sum
            WHEN (0 IS NOT NULL ) THEN (0 )::real
            ELSE NULL::real
        END  AS "committed",
        CASE
            WHEN (purchases.sum IS NOT NULL ) THEN purchases.sum
            WHEN (0 IS NOT NULL ) THEN (0 )::real
            ELSE NULL::real
        END  AS on_order,
        CASE
            WHEN (stock.quantity IS NOT NULL ) THEN stock.quantity
            WHEN (0 IS NOT NULL ) THEN (0 )::real
            ELSE NULL::real
        END  AS on_hand
   FROM (((peachtree.tbl_item items

Is this expected behavior?  Should I be concerned?  Is the modified query
faster?  Better in some way?  Should I be writing my queries to conform with
the modified syntax?

Kind Regards,
Keith

______________________________________________
99main Internet Services http://www.99main.com


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