SQL with one column - check if row exists

Question

I stuck on something stupid.. I have the table that has only one column. I want to check if there is some value, which I get from the url (method $_GET)

 mysql_connect("localhost", "user", "pass") or die(mysql_error());
 mysql_select_db("db") or die(mysql_error());

 $row=htmlspecialchars($_GET['row']);

 $query = @mysql_query ("SELECT * FROM table WHERE row=$row");


 if ($result = @mysql_fetch_array($query)) { 

 echo "There is that row";
 }


 else {
 echo "There is not that row";
 }

Can you tell me what's wrong?

as result I get "There is not that row" even if it is there – ჯ ბოლ Apr 01 '14 at 12:02 — ჯ ბოლ, Apr 01 '14 at 12:02

score 1 · Answer 1 · edited Jun 20 '20 at 09:12

The correct way would be to check if the resultset contains any rows. You can do this with mysql_num_rows():

if (mysql_num_rows($query)>0) {
 echo "There is that row";
}
else {
 echo "There is not that row";
}

Also if your $row is a string, you should enclose it in single quotes.

Note:

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 They are no longer maintained and are officially deprecated.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.

score 0 · Answer 2 · answered Apr 01 '14 at 12:04

Obligatory "you should be using PDO" comment.

You don't say what sort of field it is, maybe it is a text field so it needs to be in quotes.

$query = @mysql_query ("SELECT * FROM table WHERE row='" . $row . "');

Also if you remove the @ you might get to see some sort of error

$query = mysql_query ("SELECT * FROM table WHERE row='" . $row . "') or die(mysql_error());

score 0 · Answer 3 · edited May 24 '14 at 00:13

0

You seem to mix row and column. When querying SQL database you usually specify clumnName="value" after WHERE statement. You have valid syntax for a table with one column named "row".

There might be a problem in your query as you do not escape your arguments, so it will fail it $row actually has any quotes in it. This would be avoided with use of PDO instead of mysql_ functions which are no longer maintained. Query your table like this instead:

$query = @mysql_query("SELECT * FROM gvar WHERE gvarebi='{addslashes($row)}'");

To actually check if there are any results, it is better to use mysql_num_rows as it will return number of rows for specified query. So update your code with this:

if (mysql_num_rows($query) > 0) {
    echo "row exists";
} else {
    echo "row does not exists";
}

edited May 24 '14 at 00:13

BenMorel

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answered Apr 01 '14 at 12:05

ek9

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result is the same, I get the message "row does not exists" =( – ჯ ბოლ Apr 01 '14 at 12:14
Here is the exact code: $gvari=htmlspecialchars($_GET['gvari']); $query = @mysql_query ("SELECT * FROM gvarebi WHERE gvari=''"); if (mysql_num_rows($query) > 0) { echo "

row exists"; } else { echo "

row does not exists"; } – ჯ ბოლ Apr 01 '14 at 12:15
please provide information on what is $row ($gvari) set to. Also, what is the name of the column in the table, I am sure it is not "row"? – ek9 Apr 01 '14 at 12:15
I have poor English, so please forgive me If I understand incorrectly. The table is called "gvarebi", the column is called "gvari". Here you can see: http://tyche.ge/table.jpg – ჯ ბოლ Apr 01 '14 at 12:23
I have updated my answer (see ` $query = ...`). If that does not solve it, then you might have problems with UTF-8 encoding – ek9 Apr 01 '14 at 12:27

SQL with one column - check if row exists

3 Answers3

Note: