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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