Re: Converting join'ed rows into a comma or space delimited list

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От Mike Christensen
Тема Re: Converting join'ed rows into a comma or space delimited list
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Msg-id AANLkTinrnwWHmdfDmEV5hAhwnHYzHmhgOCz2BuKNWGXu@mail.gmail.com
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Ответ на Re: Converting join'ed rows into a comma or space delimited list  (Thom Brown <thom@linux.com>)
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Thanks!  Yup the LEFT JOIN is probably a cleaner syntax over the nested query..

On Thu, Aug 12, 2010 at 1:37 AM, Thom Brown <thom@linux.com> wrote:
> On 12 August 2010 09:16, Mike Christensen <mike@kitchenpc.com> wrote:
>> Damn I'm the master at posting stuff then figuring it out like 5
>> seconds later..  Is there an approach better than this?
>>
>> select RecipeId, Rating, array_to_string(ARRAY(select Tag from
>> RecipeTags where RecipeId = R.RecipeId), ' ') from Recipes R;
>>
> How about this:
>
> SELECT recipes.recipeid, recipes.name,
> array_to_string(array_agg(recipetags.tag), ' ')
> FROM recipes
> LEFT JOIN recipetags ON recipes.recipeid = recipetags.recipeid
> GROUP BY recipes.recipeid, recipes.name;
>
> Although in 9.0 you'll be able to do this:
>
> SELECT recipes.recipeid, recipes.name, string_agg(recipetags.tag, ' '
> ORDER BY recipetags.tag)
> FROM recipes
> LEFT JOIN recipetags ON recipes.recipeid = recipetags.recipeid
> GROUP BY recipes.recipeid, recipes.name;
>
> --
> Thom Brown
> Registered Linux user: #516935
>

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