From: | ml(at)ft-c(dot)de |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: SELECT statement with sub-queries |
Date: | 2017-05-28 18:19:59 |
Message-ID: | 6ca7f542-8add-18e1-3590-49c3ae2a4b22@ft-c.de |
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Thread: | |
Lists: | pgsql-general |
Hallo,
SELECT *
FROM products
WHERE exists
(SELECT categories.cat FROM categories WHERE
categories.serial==products.category);
or
SELECT * FROM products
WHERE category IN
(SELECT categories.cat FROM categories);
On 28.05.2017 19:03, Michelle Konzack wrote:
> Hello *,
>
> I try to get columns from my database with a singel SELECT, but I stuck.
>
> I have 3 tables like:
>
>
> 1) categories (serial,cat)
>
> 2) manufacturers (serial,m_name)
>
> 3) products (serial,category,manufacturer,p_name)
>
>
> where the "category" and "manufacturer"
> are numerical IDs from the two tables above.
>
> So I like to replace the numerical IDs with the appropriated values,
> mean
>
> SELECT * FROM products WHERE category IN
> (SELECT categories.cat FROM categories WHERE
> categories.serial==products.category);
>
> But I get:
>
> ERROR: operator does not exist: integer==integer
> LINE1: ...gories.cat FROM categories WHERE categories.serial==products.category);
> ^
> Hmm, "serial" is an "integer" and the "category" and "manufacturer" too.
>
> So whats wrong with it?
>
>
>
>
>
>
>
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