Re: 3 SELECTs rolled into 1 ?

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От A. Kretschmer
Тема Re: 3 SELECTs rolled into 1 ?
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Msg-id 20080604075546.GB24432@a-kretschmer.de
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Ответ на 3 SELECTs rolled into 1 ?  (Tarlika Elisabeth Schmitz <postgresql@numerixtechnology.de>)
Ответы Re: 3 SELECTs rolled into 1 ?  (Tarlika Elisabeth Schmitz <postgresql@numerixtechnology.de>)
Список pgsql-sql
am  Wed, dem 04.06.2008, um  8:41:29 +0100 mailte Tarlika Elisabeth Schmitz folgendes:
> I have 3 similar SELECTs. I am wondering whether they could be rolled
> into one?
> 
> 
> SELECT
>  item.id 
>  department.id || section.id || category.id as x

Syntax error, missing , between the columns ;-)



> FROM item
>  LEFT JOIN product ON ...
>  LEFT JOIN department ON ...
>  LEFT JOIN section ON ...
>  LEFT JOIN category ON ...
> 
> SELECT
>  item.id 
>  department.id || section.id as x
> FROM item
>  LEFT JOIN product ON ...
>  LEFT JOIN department ON ...
>  LEFT JOIN section ON ...
> 
> SELECT
>  item.id 
>  department.id as x
> FROM item
>  LEFT JOIN product ON ...
>  LEFT JOIN department ON ...


If i understand you correctly: use UNION, like 

select foo1 as foo, bar1 as bar from table1 UNION ALL select foo2, bar2 from table2;

The result table contains 2 columns foo and bar and all rows from both
selects.

Andreas
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