So I have the code:
$sql = "SELECT * from users WHERE level = 2";
$result = mysql_query($sql);
while($write = mysql_fetch_array($result)){
echo ''.$write['username'].'';
}
I want to make it more simple so I do:
while($write = mysql_fetch_array(mysql_query("SELECT * from users WHERE level = 2"))){
echo ''.$write['username'].'';
}
Why the first code isn't infinity looping and the second code is?
the first code iterates a resource given by mysql_query($sql);
the second iterates the query and loads the first row each time forever.
so instead of going to the next row, it makes a new query and starts on that row.
As a side note - dont use mysql_* functions. Use mysqli_ or pdo instead.
It is because your query is inside which tells the while to execute the query again and again. If you are looking for a much simpler alternative, you can try using an ORM such phpactiverecord.
Related
hi guy's i have a question.
how to declare a multiple where clause condition inside one php only.
i have try to make my project has a minimum of a php file. i want to make my where clause inside one php file only.
this is the problem i mean. i want to put my code into one php file or inside one <?php ?>. the php code like this
<?php
include("../../Connections/koneksi.php");
$date1= $_POST['date1'];
// Data for Titik1
$sql = "SELECT * FROM termocouple where tanggal='$date1' AND silo='Silo 1'";
$query = mysqli_query($db,$sql);
$rows = array();
while($tmp= mysqli_fetch_assoc($query)) {
$rows[] = $tmp;
}
echo json_encode($rows);
mysqli_close($db);
?>
on the code above the query has select table termocouple and the filter of where condition is tanggal and silo. now the problem is i have 12 php file like that. and the different of every php is from the selecting silo, i put Silo 1,Silo 2,Silo 3, ....Silo 12.
please someone help me with this. i want to make it simple in one php file. im really appreciated when you give me an example
In order to minimize your code, if you are using the same query or code more than one time in the same project, it is more recommended to create a function, that you will call anytime you need to execute the code.
So here, since you are using the same query 12 times, you will have to create a function that executes this query, and then call this function every time you want to execute the query.
The function takes parameters, so you will have to give the function the database connection parameter $db in order to connect to the database since you are using this connection inside the function, and then you have to add the values of the where clause to the parameters also.
So your function here will take the database connection $db, $date1 fetched from $_POST, and $silo fetched from $_POST
At the end of the function, you can return any value you wish to return, so in your case, you will have to return the $rows array fetched from the query
Create a common php fileand create a function in it.
Lets say the file name is libraries.php
in this file write the following code:
<?php
function getRows($db, $date, $silo) {
$sql = "SELECT * FROM termocouple where tanggal='$date' AND silo='$silo'";
$query = mysqli_query($db, $sql);
$rows = array();
while($tmp= mysqli_fetch_assoc($query)) {
$rows[] = $tmp;
}
return json_encode($rows);
}
?>
And in each of the files where you are calling the query you will remove the php code and replace it with the following:
<?php
include("../../Connections/koneksi.php");
include("{path-to-file}/libraries.php");
$date1= $_POST['date1'];
$silo = $_POST['silo'];
$rows = getRows($db, $date1, $silo) ;
?>
I am assuming these 12 PHPs are called in diff scenarios. Why dont you pass some param from client side so that the PHP knows which scenario to execute.
$date1= $_POST['date1'];
$silo= $_POST['silo'];//This could be 'Silo 1 OR 'Silo 2' etc.
// Data for Titik1
$sql = "SELECT * FROM termocouple where tanggal='$date1' AND silo='$silo'";
$query = mysqli_query($db,$sql);
I know this is something simple. I'm just forgetting something.
I'm counting the values of the rows in the "numberattending" column of my database.
When I run the SQL statement
SELECT COUNT(numberattending) AS Total FROM RSVP
in the mySQL window I get the total I'm looking for.
When I try to extract that value and echo "num_seats" I get "Resource id #3"
$num_seats = mysql_query("SELECT COUNT(numberattending) AS Total FROM RSVP", $connection);
echo $num_seats;
What I'm I missing?
Thanks for any help ahead of time.
$num_seats represents a MySQL Resource, not the value of the field selected. You'll need to use either mysql_fetch_array() or mysql_fetch_object() depending on which you prefer.
For example:
$number = mysql_fetch_array($num_seats);
echo $number['Total'];
It's also worth noting that the mysql_* family of functions are now deprecated, and you should really be using MySQLi or PDO.
You need to loop through the result sets:
From the PHP site:
// Use result // Attempting to print $result won't allow access to
information in the resource // One of the mysql result functions must
be used // See also mysql_result(), mysql_fetch_array(),
mysql_fetch_row(), etc.
$num_seats = mysql_query("SELECT COUNT(numberattending) AS Total FROM RSVP", $connection);
while ($row = mysql_fetch_assoc($num_seats )) {
echo $row['total'];
}
PS: As others will surely tell you, use of the mysql* functions have been deprecated. Look for the mysqli functions instead.
Try
$query = mysql_query("SELECT COUNT(numberattending) AS Total FROM RSVP", $connection);
$result = mysql_fetch_row($query);
echo $result['Total'];
I am trying to query a database, but it seems to just load for an age and not do anything. It's a simple query and shouldnt take longer than a millisecond.
while($row = mysql_fetch_array(getWallPosts($userid)))
{
}
Now when I replace this code with:
echo mysql_num_rows(getWallPosts($userid));
It just displays '1' in fact there's only one record in the DB and it's just a simple SELECT statement.
Here's the getWallPosts function:
function getWallPosts($userid, $limit = "10")
{
$result = dbquery("SELECT * FROM commentpost
WHERE userID = ".$userid."
ORDER BY commentPostID DESC LIMIT 0, ".$limit);
return $result;
}
Also, when I put the SQL string that it's executing into MySQL's query browser. It takes no time at all.
Any ideas?
You appear to be looping indefinitely because you're retrieving a new set (one record) of data each time.
$result = getWallPosts($userid);
while ($row = mysql_fetch_array($result)) {
//printf($row[0]);
}
You need to get the data once and loop through it. Your code is getting the data, running the loop and then getting the data again.
Try:
$posts = getWallPosts($userid);
while($row = mysql_fetch_array($posts))
{
//Code to execute
}
Its an infinite loop. The expression in the while always executes so it will always be true.
You're returning a new result set each time the while statement executes. You should call getWallPosts first, assign it to $results, and then loop over it.
i've just changed from ASP to php and i'm a bit confused about the way php is handling recordsets.
i'd like to know if there's an easier way to iterate a recordset by creating a php class.
here's the ASP syntax to show what i mean:
sq = "select * from myData"
set rs = db.execute(sq)
do while not rs.eof
response.write rs("name") // output data (response.write = echo)
rs.movenext
loop
any ideas?
thanks
You'd pretty much do the same thing...
$sql = "select * from myData";
$result = mysql_query($sql) or die(mysql_error()); //executes query
while($row = mysql_fetch_array($result)){ //will automatically return false when out of records
echo $row['name'];
}
You're probably looking for a function contains word fetch in it's name.
E.g. mysql_fetch_assoc() or $pdo->fetchAll().
Most of database API functions in PHP returns some sort of pointer variable called "resource", which can be passed to the fetch-family function, like this:
$res = mysql_query();
while($row = mysql_fetch_assoc($res)){
echo $row['name'];
}
However, some of them (like PDO's fetchAll method) returns but regular PHP array, which you can iterate using as regular foreach operator.
Is there a PHP function to get the full result with a mysql query in a multidimensional array?
SELECT * FROM table
Usually I would make something like this:
$query = mysql_query = ("SELECT * FROM table");
while ($result = mysql_fetch_array($query){
echo $result[0];
}
You can create your own function like mysql_fetch_array_complete() and imagine that it's builtin ;-)
If you are using PDO to access mysql there is.
http://www.php.net/manual/en/pdostatement.fetchall.php
Otherwise you need to do it yourself.
$query = mysql_query = ("SELECT * FROM table");
$all_results = array();
while ($result = mysql_fetch_array($query){
$all_results[] = $result;
}
print_r($all_results);
The $all_results variable will be a multi-dimensional array with all the records.
You could always write your own function to do this, but it would often lead to an unnecessary iteration through the result set (once when you call your function, another time when you actually USE the resulting array).
Since you're in php5, you could create a database result class that implements the Iterator interface. Then, you can use your class in foreach () loops and have much of the ease-of-use that you get from an array.
As of PHP 5.3 there is a built in function:
fetch_all