Issue getting num_rows with mysqli - php

I've got this code:
$query = 'SELECT * FROM users WHERE username = "' . $user . '" AND password = MD5("' . $pass . '") LIMIT 1';
echo $query;
$result = $mysqli->query($query);
echo "<br>Here: " . $result->num_rows;
Using the output from $query I put it into phpmyadmin and it returns 1 row but when trying to get the number of rows using num_rows it doesn't return anything at all - not even 0;
Any ideas?

http://ru2.php.net/manual/en/mysqli.query.php
Returns FALSE on failure.
Have you established a connectection to your DB?

Looks like the SQL query is messed up. As far as I know there is no MD5 function built into MySQL nor the SQL standard. Therefore if it does exist then it is probably proprietary to the particular DB.
That said you can use PHP to check it. Try this to see what is going on.
$encrypted_pass = md5($pass);
$query = "SELECT * FROM users WHERE username = '$user' AND password = '$encrypted_pass' LIMIT 1";
echo $query;
$result = $mysqli->query($query);
if ($result !== FALSE) {
echo "<br>Here: " . $result->num_rows;
}
else {
echo "Something is broken.";
}
Ref:
http://us2.php.net/manual/en/mysqli-result.num-rows.php

Related

Records exists but not found by query

I'm making a query to my database, but the query always return empty. If I copy the query and paste it directly to mysql, it show one record, as it should be.
This is my query in php:
$sql = "SELECT * FROM disponibilities WHERE st_week = '" .
$st_week . "' AND en_week = '" . $en_week . "' AND boat = '" .
$_POST['boat'] . "'";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
// output data of each row
while ($row = mysqli_fetch_assoc($result)) {
$disponibility = $row;
}
} else {
echo "0";
echo $_POST['boat'];
}
And this is the query (echo of the previous query) that show one record if used in phpmyadmin:
SELECT * FROM disponibilities WHERE st_week = '2021-11-13' AND en_week = '2021-11-20' AND boat = 'sapphire'
I've tried converting the date in this way, but still don't work
$sql= "SELECT * FROM disponibilities WHERE st_week =
STR_TO_DATE('$st_week','%Y-%m-%d') AND en_week = STR_TO_DATE('$en_week','%Y-%m-%d')";
EDIT:
this is my phpmyadmin query response:
Thanks in advance
try to run
SELECT * FROM disponibilities WHERE st_week = '2021-11-13' AND en_week = '2021-11-20' AND boat = 'sapphire';
this query from your code what i mean is that run the query with static values instead of variables and see if it returns anything if it does then you are getting wrong value in your variables...
let me if this is the problem if not also so that i can help you further...

mysql query works with plain text, but not with variable

I am trying to print out some topic information, but it is not going so well. This is my query:
SELECT * FROM topics WHERE id='$read'
This doesn't work. I've echo'ed the $read variable, it says 1. So then if I do like this:
SELECT * FROM topics WHERE id='1'
It works perfectly. I don't get what is the problem. There's no hidden characters in $read or anything else like that.
Try like this:
$query = "SELECT * FROM topics WHERE id='" . $read . "'"
ID is normally a numeric field, it should be
$id = 1;
$query = "SELECT * FROM topics1 WHERE id = {id}"
If you are using strings for some reason, fire a query like
$id = '1';
$query = "SELECT * FROM topics1 WHERE id = '{$id}'"
SELECT * FROM topics WHERE id=$read
it consider it as string if you put i single quotes
I wonder why all the participants didn't read the question that clearly says that query with quotes
SELECT * FROM topics WHERE id='1'
works all right.
As for the question itself, it's likely some typo. Probably in some other code, not directly connected to $read variable
try
$query = sprintf("SELECT * FROM topics WHERE id='%s';",$read);
Also remember to escape the variable if needed.
Looks like you might have an issue with the query generation as everyone else is pointing to as well. As Akash pointed out it's always good to build your query in to a string first and then feed that string to the MySQL API. This gives you easy access to handy debugging techniques. If you are still having problems try this.
$id = 1;
$query = "SELECT * FROM `topics1` WHERE `id`={$id}";
echo ": Attempting Query -> {$query}<br />";
$res = mysql_query($query, $dblink);
if($res <= 0)
die("The query failed!<br />" . mysql_error($dblink) . "<br />");
$cnt = mysql_num_rows($res);
if($cnt <= 0)
{
$query = "SELECT `id` FROM `topics1`";
echo "No records where found? Make sure this id exists...<br />{$query}<br /><br />";
$res = mysql_query($query, $dblink);
if($res <= 0)
die("The id listing query failed!<br />" . mysql_error($dblink) . "<br />");
while($row = mysql_fetch_assoc($res))
echo "ID: " . $row['id'] . "<br />";
}
This will at least let you monitor between calls, see what your query actually looks like, what mysql says about it and if all else fails make sure that the ID you are looking for actually exists.
try with this : SELECT * FROM topics WHERE id=$read

search SQL for possibly duplicated user names using PHP

I want to search my database to see if a user that is registering is using a username that is currently in my database. I have registered the same name about 5 times so it SHOULD return false but it returns true.
<?php
function registerUser($userName, $userPassword) {
$db = new dbinterface();
$db->connect();
// check for duplicate data
$checkduplicates = "SELECT * FROM usersexample WHERE $userName = :userName";
$myresult = mysql_query($checkduplicates);
if(mysql_num_rows($myresult) > 0){
echo $myresult;
return false;
}
?>
My table name is usersexample and the field i am searching is userName.
ANY and ALL help is appreciated!
Using mysql_num_rows in examples i get this warning:
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource.
Use mysql_num_rows() to check the number of rows returned.
Sample:
$myresult = mysql_query($checkduplicates);
$rowcount = mysql_num_rows($myresult);
if($rowcount > 0)
{
// Account name already in use
}
You should try this...
if(mysql_num_rows($myresult) > 0) {
echo $myresult;
return false;
}
It will return false if there is a duplicate username.
$getduplicates = mysql_query("SELECT * FROM table WHERE username = $username");
$duplicates = mysql_num_rows($getduplicates);
if($duplicates){
echo "Uh oh someone already has that username";
}
else {
echo "Everything is allllllll good";
}
Please use prepared statements to avoid sql injection.
As you are using :userName in your SQL it seems you are trying to do this (is your
database class based on PDO by any chance?). The :userName part will be replaced
by your variable $userName when you do the bindValue.
Use count() in the database to count the number of records found,
the database knows best ;-)
$query = $db->prepare("SELECT count(*) AS no_found FROM usersexample WHERE userName = :userName");
$query->bindValue(':userName', $userName, PDO::PARAM_STR);
$query->execute();
$result = $query->fetchObject();
if($result->no_found > 0)
{
return false;
}
Did you try:
$checkduplicates = "SELECT userName FROM usersexample
WHERE LOWER('".$userName."') = LOWER(userName)";
$myresult = mysql_query($checkduplicates)
if (!$myresult) {
die('Invalid query: ' . mysql_error());
} else {
$num_rows = mysql_num_rows($myresult);
if (!$num_rows) {
die('Invalid query: ' . mysql_error());
} else return ($num_rows == 0);
}
Please, sanitize user input to avoid SQL injection.
I don't know if you are doing something fancy I don't understand, but I would build the query like this:
$checkduplicates = "SELECT * FROM `usersexample` WHERE `userName` = '$userName'";
Or this
$checkduplicates = "SELECT * FROM `usersexample` WHERE `userName` = '".$userName."'";

Check if value is in mysql's table's column

How can I check if value is in mysql's table's column?
Right now I'm creating a login system. After the user registers my php file posts the value and makes it into a variable. I was wondering what code i can use to compare my value to those values in the table and to check whether or not there is a value identical to the value entered.
I tried this code.
$query = "SELECT * FROM users WHERE username ='$username';";
$res = mysql_num_rows(mysql_query($query));
and then if ($res >= 0);
but then i get this error,
Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/synameg1/public_html/giveaway/appfiles/register.php on line 23
so i was wondering if there is either a way to fix this error or do what i want to do in another method.
Thanks!
$sql = "SELECT * FROM users WHERE username = '" . mysql_real_escape_string($username) . "'";
$result = mysql_query($sql) or die("Error occurred in [$sql]: " . mysql_error());
$count = mysql_num_rows($result);
Dan: I used your approach with 'zero' result.
<?php
//////////////////////////////////////////////////////////////////////
global $current_user;
get_currentuserinfo();
$user_nam = $current_user->user_login;
$db_host = 'localhost';
$db_user = 'Private'; ////the user name
$db_pwd = 'Private'; /////the pasword
$database = 'Datapase name';/////////
$table = 'Table Name'; ///table name
$sql = "SELECT * FROM $table WHERE 'Submitted Login' = '" . mysql_real_escape_string($user_nam) . "'";
$result = mysql_query($sql) or die("Error occurred in [$sql]: " . mysql_error());
$count = mysql_num_rows($result);
echo $user_nam . "<br />";
echo "count is $count";
////////////////////////////////////////////////////////////////////
?>
Private fields have comments.
It works, I can see $user_nam but the count is zero.
Here is a datebase peek so you can see the values.
http://you-get-real.com/images/database-peek.png
Thanks

selecting row from mysql if id matches

I want to select a row from mysql which matches a specific id. I want to get the result if the ID matches, if the ID does not exists in the database, it should not do anything.
I run sth like this:
$q = "SELECT * FROM entries where id= '1'";
$result = mysql_query($q) or die(mysql_error());
if($result){
$row = mysql_fetch_array($result) or die(mysql_error());
$name = $row['name'];
}
echo "hello".$name;
If the id '1' exists in the db, it should get the name, otherwise nothing or at least it should give the error, but when i use this, it just display no any content of the page which comes after this code. What I'm doing wrong?
If it does not display any code after this code, this is probably due to an error occuring and your error handling being set so the error is not displayed.
Try searching for the php error log file (normaly php_error.log) that should contain the error that you do not see.
Another thing i would try is adding more echo statements to see where exactly php stops interpreting.
Like this:
$q = "SELECT * FROM entries where id= '1'";
$result = mysql_query($q);
echo '<br />Query is send';
if(!$result) {
die('<br/>MySQL Error: ' . mysql_error());
}
else {
echo '<br />Result is true';
$row = mysql_fetch_array($result);
echo '<br />tryed fetching row';
if ($row === FALSE) {
echo '<br />$row is not false.';
$name = $row['name'];
echo '<br />$name now is "' . $name . '"';
}
else {
die('<br/>MySQL Error: ' . mysql_error());
}
}
echo '<br />hello: "' . $name . '"';
That might help to get some more information about your problem.
$id = 1;
$sql = "SELECT `name` FROM `entries` WHERE `id` = $id LIMIT 1" //Since the id is probably an integer type on the DB, the single quotes aren't necessary, and sometimes screw it up. I think MySQL possibly thinks it's a string when in quotes.
$result = mysql_query($sql) or die(mysql_error());
if(mysql_num_rows($result))
{
$row = mysql_fetch_assoc($result) or die(mysql_error());
$name = $row['name'];
echo 'Hello ' . $name;
}
A SELECT query can return 0 rows if the condition you specified doesn't match any rows, and that isn't an error.
You should rather check the result of mysql_num_rows() after sending the query.
Maybe you should add a else statement to your if.
if($result)
....
else
do something
You might even want to do a try catch statement.

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