Question

I would use only a single query:

$sql = "UPDATE gallery SET order = (order+1) WHERE id_categ = ".$id;
$res = mysql_query($sql);

...

Is it possible?

Answer 1

mysql_affected_rows()

mysql_affected_rows — Get number of
affected rows in previous MySQL
operation

Example:

$sql = "UPDATE gallery SET order = (order+1) WHERE id_categ = ".$id;
$res = mysql_query($sql);
printf("Affected rows: %d\n", mysql_affected_rows());

Note that the mysql_affected_rows() return you the affected rows whether updated/deleted of your last run query. For example:

$sql = "UPDATE gallery SET order = (order+1) WHERE id_categ = ".$id;
$res = mysql_query($sql);

$sql = "UPDATE gallery2 SET order = (order+1) WHERE id_categ = ".$id;
$res = mysql_query($sql);

Now if you do:

printf("Affected rows: %d\n", mysql_affected_rows());

It will return the affected rows for the last query that is gallery2 table’s query.

More Info:

• http://php.net/manual/en/function.mysql-affected-rows.php