problem with operators in Mysql `select` query

Question

I'm new in MySQL and trying to filter users base on age, gender, and chat_id,

with below query:

SELECT * FROM Users WHERE
age = 17
AND gender='$gender1' OR gender='$gender2'
AND chat_id <> '$chat_id'
LIMIT 1

when $age is 17, i get unexpected result and $age is not considered.

What am I missing?

What does "age = 17 doesn't working" mean? You get an error? unexpected results? What? — HoneyBadger, Jan 10 '17 at 16:58
[Little Bobby](http://bobby-tables.com/) says ***[your script is at risk for SQL Injection Attacks.](http://stackoverflow.com/questions/60174/how-can-i-prevent-sql-injection-in-php)***. Learn about [prepared](http://en.wikipedia.org/wiki/Prepared_statement) statements for [PDO](http://php.net/manual/en/pdo.prepared-statements.php) and [MySQLi](http://php.net/manual/en/mysqli.quickstart.prepared-statements.php) and consider using PDO, [it's really pretty easy](http://jayblanchard.net/demystifying_php_pdo.html). — Jay Blanchard, Jan 10 '17 at 16:59
i get unexpected result and age is not considered in final result — Saadat, Jan 10 '17 at 17:01
This is a question about logical evaluation. You _probably_ need some brackets around `(gender='$gender1' OR gender='$gender2')`... — arkascha, Jan 10 '17 at 17:02

score 1 · Accepted Answer · edited Jan 11 '20 at 10:45

1

Change this:

AND gender='$gender1' OR gender='$gender2'

to this:

AND (gender='$gender1' OR gender='$gender2')

You can additionally read about operators here.

edited Jan 11 '20 at 10:45

answered Jan 10 '17 at 17:02

Dan Bracuk

@SaadatEsmaeily Although adding parenthesis will 'fix' your query, please check the comment by Jay Blanchard – Robert Jan 10 '17 at 17:11
A little explanation of the solution would be helpful to future readers. – showdev Jan 12 '17 at 20:33

1 Answers1