updating a table with conditional check

Question

I am creating a website for book rental system. Here I do the work of librarian where inserting the book details are done. So here i want to update the availability of the book if the name of the book is already inserted. My query goes like this. And whenever I try to update the availability of the book the value again gets inserted.

$name=$_POST['bname'];
$avail=$_POST['avail'];
$q=mysql_query("select * from table where name='$name'");
if($name==$q){
  $n=("update table where name='$name' set avail='$avail'+1")
}

why are you still using mysql extension – Muhammad Feb 21 '14 at 06:55 — Muhammad, Feb 21 '14 at 06:55

score 3 · Accepted Answer · edited May 25 '19 at 13:58

3

Should be,

UPDATE table 
SET `avail`= `avail` + 1
WHERE name = '$name'

Warning: Please, don't use mysql_* functions in new code. They are no longer maintained and are officially deprecated. See the red box? Learn about prepared statements instead, and use PDO, or MySQLi - this article will help you decide which. If you choose PDO, here is a good tutorial.

edited May 25 '19 at 13:58

Zoe

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answered Feb 21 '14 at 06:34

Rikesh

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score 1 · Answer 2 · answered Feb 21 '14 at 06:41

1

Your update query is wrong . Use this

"update table set avail = avail+1 where name = '$name'";

answered Feb 21 '14 at 06:41

Deepu Sasidharan

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score 1 · Answer 3 · answered Feb 21 '14 at 06:53

1

I think the first query must be change like this:

'SELECT name FROM table WHERE name='.$name

and second one:

'UPDATE table SET avail = avail+1 WHERE name ='.$name

answered Feb 21 '14 at 06:53

Morteza Tourani

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updating a table with conditional check

3 Answers3