The "-" Operator in SQL where condition

ghz 8months ago ⋅ 73 views

I am encountering a rather peculiar syntax in MySQL, specifically the presence of a '-' symbol within the WHERE condition in the following query.

SELECT 
    users.id
FROM
    users
WHERE
    users.account_status >= 3
        AND users.account_status NOT IN (8 , 9)
        AND - users.registration_status = 14
        AND users.id IN (229);

I've researched this syntax in here?

Could it possibly indicate a transformation of the value of the 'registration_status' column into a negative number?

Answers

In MySQL, the presence of a '-' symbol before a column name within a WHERE condition indicates a negation or subtraction operation. However, in the context of your query:

- users.registration_status = 14

The '-' symbol appears to be a unary negation operator applied to the value of the 'registration_status' column. This means that the expression '- users.registration_status' evaluates to the negative of the value of the 'registration_status' column.

So, the condition '- users.registration_status = 14' is checking if the negation of the 'registration_status' value is equal to 14. This is equivalent to checking if the 'registration_status' value is equal to -14.

In summary, the expression '- users.registration_status' is not transforming the value of the 'registration_status' column into a negative number, but rather applying a negation operation to that value within the context of the WHERE condition.

#mysql