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Fatal error: Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'where ip_address='::1'' at line 1 in C:\xampp\htdocs\food project\cart.php:141 Stack trace: #0 C:\xampp\htdocs\food project\cart.php(141): mysqli_query(Object(mysqli), 'update cart set...') #1 {main} thrown in C:\xampp\htdocs\food project\cart.php on line 141

What I have tried:

$result="update cart set quantity=$quantity where ip_address='$ip'";
Updated 22-Dec-22 21:41pm
0x01AA 23-Dec-22 3:33am    
Try where ip_address = $ip

1 solution

Don;t do it like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.

When you concatenate strings, you cause problems because SQL receives commands like:
SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'
The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:
SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;--'
Which SQL sees as three separate commands:
SELECT * FROM MyTable WHERE StreetAddress = 'x';
A perfectly valid SELECT
A perfectly valid "delete the table" command
And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.

So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?

Fix that through your whole app, and the problem you have noticed will go away at the same time.
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0x01AA 23-Dec-22 3:58am    
For me it looks like he allready uses a parametrized query, but put quotes around the parameter...
Or I miss something ;)
OriginalGriff 23-Dec-22 4:33am    
It's PHP - so variables start with "$" and strings with double quotes use string interpolation, replacing variable names with their content.
0x01AA 23-Dec-22 4:40am    
Thank you very much.
OriginalGriff 23-Dec-22 4:43am    
You're welcome!

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