Re: [GENERAL] SELECT statement with sub-queries

On 2017-05-29 03:24:54 rob stone hacked into the keyboard:
> You only need a single equals sign in SQL.
>
> SELECT * FROM products WHERE category IN 
>     (SELECT categories.cat FROM categories WHERE 
>     categories.serial = products.category);

I have tried this too, but then I get:

ERROR:  operator does not exist: integer = character varying
LINE 1: SELECT * FROM products WHERE category IN (SELECT categories....
                                              ^

My sql file is:

----8<------------------------------------------------------------------
DROP TABLE categories;
DROP TABLE manufacturers;
DROP TABLE products;

CREATE TABLE categories (
    serial        integer NOT NULL,
    cat        varchar(40),
);

CREATE TABLE manufacturers (
    serial        integer NOT NULL,
    m_name        varchar(40),
    m_address    varchar(200),
    m_images    varchar(100),
    m_desc        varchar(1000),
);

CREATE TABLE products (
    serial        integer NOT NULL,
    category    integer NOT NULL,
    manufacturer    integer NOT NULL,
    p_name        varchar(40),
    p_images    varchar(100),
    p_desc        varchar(10000),
);
----8<------------------------------------------------------------------

This is WHY I am puzzeling arround with the "integer" error.


--
Michelle Konzack        Miila ITSystems @ TDnet
GNU/Linux Developer     00372-54541400