I want to select an id from a table using the query:
$demo_id = mysql_result(mysql_query("SELECT id FROM demo_tbl WHERE a_val='a' and b_val='b' LIMIT 1"),0);
This query works perfectly if it satisfies the condition. But if there is no such record then the above mentioned error shows. I dont want to use mysql_num_rows(). Is there any way to find whether $demo_id has value or not.
if(!$demo_id){
//no return
}else{
//demo_id has value
}
base on the manual:
http://php.net/manual/en/function.mysql-result.php
if you are not using mysqli_num_rows() then you try this
if (empty($demo_id)) {
echo 'No results found';
} else {
echo implode($demo_id);
}
and also i mention that don't use mysql_*.. you should use mysqli_*
Mysqli_* manual
Related
I am try to fetch data from the database
$check_sql = 'SELECT * FROM table;
$check_result = mysql_query($check_sql);
echo $check_result;
$result = mysql_fetch_array($check_result);
when I echo $check_result, it shows 'Resource id 2', which i think it means there exists a return array, but when I use mysql_fetch_array, it will return a null value, and I don't know why...And I found that no matter whether there exists the resules or not, echo $check_result would always shows 'Resource id#2', does this sentence in mysql mean 'no results' ? Could someone help???
In case if you are dealing with multiple rows in your mysql query you need to use code like this:
while ($row = mysql_fetch_array($check_result) )
{
echo $row['ROW_NAME_HERE'];
}
I guess it is why you mentioned mysql_fetch_array function.
mysql_fetch_array() returns an array.
You definitely must take a look at documentation http://php.net/mysql_fetch_array
Try print_r($result);
<?php
$uname=$_POST['uname'];
$pwd=$_POST['pwd'];
$result="";
echo($uname.'</br>');
echo($pwd);
$con=mysql_connect("localhost","root","");
mysql_select_db("user_login_test",$con);
$sql="SELECT * FROM userlogin WHERE username='".$uname."'";
if($result=mysql_query($sql))
{
echo($result);
echo("Extracted<br>");
}
else
{
echo("NOT Extracted");
}
while($row = mysql_fetch_array($result))
{
echo $row['username'] . " " . $row['password'];
echo "<br />";
}
?>
I am doing above code for extracting values. If Username matches it show the value but if I give wrong input text it also shows "Extracted" with no value why? Please help me???
As explained in the PHP manual entry for the mysql_query() function:
For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset, mysql_query() returns a resource on success, or FALSE on error.
Your $result variable therefore holds a MySQL resource irrespective of whether there is a match on the username column: testing such a resource using if will always evaluate to TRUE (unless the query itself threw an error).
The manual goes on to explain:
The returned result resource should be passed to mysql_fetch_array(), and other functions for dealing with result tables, to access the returned data.
Use mysql_num_rows() to find out how many rows were returned for a SELECT statement or mysql_affected_rows() to find out how many rows were affected by a DELETE, INSERT, REPLACE, or UPDATE statement.
In your case, you could test using mysql_num_rows() to determine whether any records were returned by the query (i.e. whether the WHERE condition was satisfied).
You have write wrong logic for extract username.
I have modify your code check it.
$sql="SELECT * FROM userlogin WHERE username='".$uname."'";
$result=mysql_query($sql)
if(mysql_num_rows($result)>0)
{
echo("Extracted<br>");
}
else
{
echo("NOT Extracted");
}
Why won't this query work?!?
Error
Parse error: syntax error, unexpected T_STRING in E:\xampp\htdocs\pf\shop\buy.php on line 5
Example Info For Variables
$character->islots = 20
$chatacter->name = [RE] Tizzle
$e2 = 10
The Function
function increaseSlots($e2) {
$slots = ($character->islots)+($e2);
mysql_query('UPDATE `phaos_characters` SET `inventory_slots`="'.$slots.'" WHERE `name`="'.$character->name.'"'); // <-- Line 5
if (mysql_affected_rows() != 0) {
echo 'Inventory Size Incresed By '.$e2.' Slots';
}else{
echo mysql_error();
}
}
Look at the docs: http://php.net/manual/en/function.mysql-num-rows.php
Retrieves the number of rows from a result set. This command is only valid for statements like SELECT or SHOW that return an actual result set. To retrieve the number of rows affected by a INSERT, UPDATE, REPLACE or DELETE query, use mysql_affected_rows().
You need to use mysql_affected_rows() or better yet, PDO or mysqli.
$slots = ($character->islots)+($e2);
Looks like there is a typo. Try:
$slots = ($character->slots)+($e2);
First off you should know that mysql_num_rows only returns a valid result for SELECT or SHOW statements, as stated in the PHP documentation. You can use mysql_affected_rows() for your particular needs.
However, the old PHP MySQL API (that you are using) is being phased out, so I would recommend using mysqli or PDO for your DB connection needs.
While keeping with your requirements, though, you can try to use the following syntax to make sure you receive the MySQL error if it throws one. Your PHP script will stop, but you will see the error.
$query = sprintf('UPDATE `phaos_characters` SET `inventory_slots`=%d WHERE `name`="%s"',$slots,$character->name)
$result = mysql_query($query) or die(mysql_error());
As a final idea, in situations like this it helps to print out your resulting $query and run it manually through something like phpMyAdmin to see what happens.
Bleh... I Found a better way to do it for the time being.. sorry to waste your guys' time...
I just threw the $character object into a variable before processing the function.
function increaseSlots($e2,$charname,$charslots) {
$slots = $charslots+$e2;
mysql_query('UPDATE `phaos_characters` SET `inventory_slots`="'.$slots.'" WHERE `name`="'.$charname.'"');
if (mysql_affected_rows() != 0) {
echo 'Inventory Size Incresed By '.$e2.' Slots';
}
}
I am trying to get the number of rows affected in a simple mysql update query. However, when I run this code below, PHP's mysql_affected_rows() always equals 0. No matter if foo=1 already (in which case the function should correctly return 0, since no rows were changed), or if foo currently equals some other integer (in which case the function should return 1).
$updateQuery = "UPDATE myTable SET foo=1 WHERE bar=2";
mysql_query($updateQuery);
if (mysql_affected_rows() > 0) {
echo "affected!";
}
else {
echo "not affected"; // always prints not affected
}
The UPDATE statement itself works. The INT gets changed in my database. I have also double-checked that the database connection isn't being closed beforehand or anything funky. Keep in mind, mysql_affected_rows doesn't necessarily require you to pass a connection link identifier, though I've tried that too.
Details on the function: mysql_affected_rows
Any ideas?
Newer versions of MySQL are clever enough to see if modification is done or not. Lets say you fired up an UPDATE Statement:
UPDATE tb_Employee_Stats SET lazy = 1 WHERE ep_id = 1234
Lets say if the Column's Value is already 1; then no update process occurs thus mysql_affected_rows() will return 0; else if Column lazy had some other value rather than 1, then 1 is returned. There is no other possibilities except for human errors.
The following notes will be helpful for you,
mysql_affected_rows() returns
+0: a row wasn't updated or inserted (likely because the row already existed,
but no field values were actually changed during the UPDATE).
+1: a row was inserted
+2: a row was updated
-1: in case of error.
mysqli affected rows developer notes
Have you tried using the MySQL function ROW_COUNT directly?
mysql_query('UPDATE myTable SET foo = 1 WHERE bar = 2');
if(mysql_result(mysql_query('SELECT ROW_COUNT()'), 0, 0)) {
print "updated";
}
else {
print "no updates made";
}
More information on the use of ROW_COUNT and the other MySQL information functions is at: http://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function_row-count
mysqli_affected_rows requires you to pass the reference to your database connection as the only parameter, instead of the reference to your mysqli query. eg.
$dbref=mysqli_connect("dbserver","dbusername","dbpassword","dbname");
$updateQuery = mysqli_query($dbref,"UPDATE myTable SET foo=1 WHERE bar=2");
echo mysqli_affected_rows($dbref);
NOT
echo mysqli_affected_rows($updateQuery);
Try connecting like this:
$connection = mysql_connect(...,...,...);
and then call like this
if(mysql_affected_rows($connection) > 0)
echo "affected";
} else { ...
I think you need to try something else in update then foo=1. Put something totaly different then you wil see is it updating or not without if loop. then if it does, your if loop should work.
You work this?
$timestamp=mktime();
$updateQuery = "UPDATE myTable SET foo=1, timestamp={$timestamp} WHERE bar=2";
mysql_query($updateQuery);
$updateQuery = "SELECT COUNT(*) FROM myTable WHERE timestamp={$timestamp}";
$res=mysql_query($updateQuery);
$row=mysql_fetch_row($res);
if ($row[0]>0) {
echo "affected!";
}
else {
echo "not affected";
}
This is because mySql is checking whether the field made any change or not,
To over come this, I created a new TINY field 'DIDUPDATE' in the table.
added this to your query 'DIDUPDATE=DIDUPDATE*-1'
it looks like.
$updateQuery = "UPDATE myTable SET foo=1, DIDUPDATE=DIDUPDATE*-1 WHERE bar=2";
mysql_query($updateQuery);
if (mysql_affected_rows() > 0)
{
echo "affected!";
}
else
{
echo "not affected";
}
it works fine!!!
Was My Tought !
I was just about to tell to check if the function's being called many times !
Just a little advice:
try using isset() & POST / GET or something like that;
if ( isset( $_POST['Update'] == 'yes' ) ) :
// your code goes here ...
endif;
Hope it was clear and useful, Ciao :)
I want to use PHP to find out if no matches are found. I tried the following, but "is_resource()" always returns true.
$result = mysql_query('...');
if(is_resource($result)){
// Results are found
}
mysql_num_rows() will do the trick.
if (mysql_num_rows($result)>0) {
//Results are found
}
http://php.net/manual/en/function.mysql-num-rows.php
So $result will always be a resource as long as you have proper access to the database. And mysql_num_rows() assumes that the query itself ran successfully. I'd say try something like this:
if($result === FALSE) // Query failed due to not having proper permissions on the table
die('Invalid query: ' . mysql_error());
else if(mysql_num_rows($result) >0)) // We have more than 1 row returned which means we have data
// INPUT RESULTS PROCESSING HERE
else // No rows were returned therefore there were no matches
echo 'No rows returned';
Hope that helps a little =)
Look here for more information if you need: http://www.php.net/manual/en/function.mysql-query.php
This is what you want: mysql_num_rows()
If the query fails it mysql_query will return false so you can check your code like this:
if ( $stmt = mysql_query("...") )
{
// Do some things
}
else
{
// Do some other things
}
Or you could use mysql_num_rows like the people above have stated.
But you should really be looking into MySQLi it's a built in database class. Learn it and use it. Your life will be so much easier.