Hello,

Some people create queries that do not work and don’t have a clue why they don’t, as no error is displayed. I’ll show you how to display the MySQL error, if any, when the query is run. A must know for programmers. Great tool for debugging queries.

1. Open the file where you have your query. For this article, I will be using the following code:

//Connection to DB already established
$query = "SELECT * FROM mytable WHERE column='value'";
$result = mysql_query($query);
while($row = mysql_fetch_array($result)) { //loop through results
 print $row['somecolumn'];
}

2. In the previous code you see that if “column” with a value of “value” existed, it would output “somecolumn”. But what if you face for example an error saying that mysql_fetch_array() doesn’t accept booleans? Then it would mean that there was a problem with the $query. To see the error, we would simply add mysql_error() function to see what’s going on.

$result = mysql_query($query) or die(mysql_error());

3. This way, we would now see if there was a problem with the query and try to fix it. Most of the time, it is a typo, a quotes problem or a nonexistent column.

So to summarize, remember to add a mysql_error() function for debugging queries. Most of the time you will see what is the problem with that. If not, feel free to contact me so I can personally assist you through the troubleshooting. Any question or comment, please write it below!

Best Regards,

Richi

Owner of Juapo2Services.com

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