false OR false = true in MySQL? Very odd behaviour

Question

Basically, my 0 OR 0 is returning 1 - that's not really what I wanted :) I'm not really sure why because if I select 0 OR 0 I get 0..

I think this could be because is_premium_dealer is an enum('0','1') rather than a bool (don't ask me why, I didn't design this database!)

Does anyone know if this is because of the ENUM, and if so how I'd cast it to an integer?

Thanks in advance! John.

SELECT is_premium_dealer, company_name,
(SELECT COUNT(*) FROM adverts WHERE user_id = users.id AND is_archived = 0) AS innerquery,
((SELECT COUNT(*) FROM adverts WHERE user_id = users.id AND is_archived = 0 AND is_deleted = 0) > 0 OR is_premium_dealer = 1) AS logicissue
FROM `user_profiles_dealers` 
LEFT JOIN `users` ON user_profiles_dealers.user_id = users.id 
LEFT JOIN `counties` ON user_profiles_dealers.county_id = counties.id 
LEFT JOIN `countries` ON user_profiles_dealers.country_id = countries.id 
WHERE (users.is_active=1) 
AND (((SELECT COUNT(*) FROM adverts WHERE user_id = users.id AND is_archived = 0 AND     is_deleted = 0) > 0) OR is_premium_dealer > 0) 
AND company_name like '%autocraft%' limit 5\G

The result:

*************************** 1. row ***************************
is_premium_dealer: 0
company_name: A Company
innerquery: 0
logicissue: 1
1 row in set (0.00 sec)

Answer 1

答案是将is_premium_dealer包装在BINARY（）函数中，该函数似乎将字符串或任何内容转换为可以按预期计算的二进制值。

Answer 2

That is because is_premium_dealer = 1 filters records by ENUM index . From the documentation - ENUM values are represented internally as integers .

The ENUM Type .

Suppose we have - enum_column ENUM('dog', 'cat', 'snake') then:

• WHERE enum_column = 1 will show records where enum_column = 'dog'
• WHERE enum_column = 2 will show records where enum_column = 'cat'
• and so on...

So, you can use number in WHERE condition and without BINARY function, just specify correct enum index.