Im trying to sum up all the values in this data base but for some reason i cant do i, I looked all over stack overflow and tried multiple methods but none seem to work. My current code is
<?php
error_reporting(0);
//INCLUDES//
include 'config.php';
//INCLUDES//
//DATA FETCH//
$rank=$_POST['R'];
$drank=$_POST['DR'];
//DATA FETCH//
//MYSQL STUFF//
$con=mysqli_connect($ip,$login,$password,$dbname);
for ($i = $rank; $i <= $drank; $i++) { // LOOP UNTIL 20 IS MET
$s=mysqli_query($con, "SELECT sum(rankprice) FROM cost WHERE rank='$i'");
if($s === FALSE) { //CHECK IF DATA IS THERE
die('Error: ' . mysqli_error($con)); // IF NOT THERE SEND ERROR
}
$row = mysqli_fetch_array($s); //PUT DATA IN ROW
echo $row[0];
}
?>
It connects to the database no problem. When I use echo $row[0]; it prints all the values of the column in order. Ive tried putting it into an array and printing it but it seems that doesnt work either. The only way it seems to work is when I add ALL the values in the column by removing WHERE rank='$i' in the SQL code which I dont want to do. Please help !
Try the following query :
$rankarr = array();
for ($i = $rank; $i <= $drank; $i++) { // LOOP UNTIL 20 IS MET
$rankarr[] = $i;
}
$rankarr = implode(',', $rankarr);
$s=mysqli_query($con, "SELECT sum(rankprice) As myrank FROM cost WHERE rank in ($rankarr)");
if($s === FALSE) { //CHECK IF DATA IS THERE
die('Error: ' . mysqli_error($con)); // IF NOT THERE SEND ERROR
}
$row = mysqli_fetch_array($s); //PUT DATA IN ROW
You now want to get the sum value of rankprice in one same rank. So the result of sum() will differ from the rank in one sql. You should tell mysql by adding group by clause, which group the table by rank and get the sum() of each group.
$s=mysqli_query($con, "SELECT sum(rankprice) FROM cost WHERE rank='$i' GROUP BY rank ");
Related
I'm creating a search box that queries two MySQL tables and lists the results in real time. For now though, I have a working prototype that will query only one table. I've written the following PHP code in conjunction with JQuery and it works wonderfully:
HTML
<input onkeyup="search(this);" type="text">
<ol id="search-results-container"></ol>
Javascript
function search(input) {
var inputQuery = input.value;
/* $() creates a JQuery selector object, so we can use its html() method */
var resultsList = $(document.getElementById("search-results-container"));
//Check if string is empty
if (inputQuery.length > 0) {
$.get("search-query.php", {query: inputQuery}).done(function(data) {
//Show results in HTML document
resultsList.html(data);
});
}
else { //String query is empty
resultList.empty();
}
}
and PHP
<?php
include("config.php"); //database link
if(isset($_REQUEST["query"])) {
$sql = "SELECT * FROM students WHERE lastname LIKE ? LIMIT 5";
/* Creates $stmt and checks if mysqli_prepare is true */
if ($stmt = mysqli_prepare($link, $sql)) {
//Bind variables to the prepared statement as parameters
mysqli_stmt_bind_param($stmt, "s", $param_query);
//set parameters
$param_query = $_REQUEST["query"] . '%';
//Try and execute the prepared statement
if (mysqli_stmt_execute($stmt)) {
$result = mysqli_stmt_get_result($stmt);
//get number of rows
$count = mysqli_num_rows($result);
if ($count > 0) {
//Fetch result rows as assoc array
$row = mysqli_fetch_array($result, MYSQLI_ASSOC);
echo "<h1>Students:</h1>"; //Header indicates student list
for ($i = 0; $i < $count; $i++) {
$name = $row["lastname"];
echo "<p>$name</p>";
}
}
else { //Count == 0
echo "No matches found.<br>";
}
}
else { //Execution of preped statement failed.
echo "Could not execute MySQL query.<br>";
}
} // end mysqli_prepare
} // end $_RESQUEST isset
?>
The details of the students table are arbitrary, except for the fact that it has a String column that lists the student's last name.
My problem is that there is also a staff table which is effectively the same as students but for a different purpose. I'd like to query the staff table at the same time as students, but have the results separated like so:
<h1>Students:</h1>
<p>Student1</p>
<p>Student2</p>
<h1>Staff</h1>
<p>Staff1</p>
<p>Staff2</p>
The obvious answer would be to add another $sql statement similar to the one on Line 5 and just do both queries serially - effectively doubling the search time - but I'm concerned this will take too long. Is this a false assumption (that there will be a noticeable time difference), or is there actually a way to do both queries alongside each other? Thanks in advance!
If the two tables have identical structures, or if there is a subset of columns which could be made to be the same, then a UNION query might work here:
SELECT *, 0 AS type FROM students WHERE lastname LIKE ?
UNION ALL
SELECT *, 1 FROM staff WHERE lastname LIKE ?
ORDER BY type;
I removed the LIMIT clause because you don't have an ORDER BY clause, which makes using LIMIT fairly meaningless.
Note that I introduced a computed column type which the result set, when ordered by it, would place students before staff. Then, in your PHP code, you would just need a bit of logic to display the header for students and staff:
$count = mysqli_num_rows($result);
$type = -1;
while ($count > 0) {
$row = mysqli_fetch_array($result, MYSQLI_ASSOC);
$curr_type = $row["type"];
if ($type == -1) {
echo "<h1>Students:</h1>";
$type = 0;
}
else if ($type == 0 && $curr_type == 1) {
echo "<h1>Staff:</h1>";
$type = 1;
}
$name = $row["lastname"];
echo "<p>$name</p>";
--$count;
}
Can't believe this is giving me a problem but here it is. An example of the query and code is:
$sql = "SELECT
o.order_id, o.order_number, o.broker_id, o.agent_id
FROM orders o";
$sql_res = safe_query($sql);
/* I want to echo broker_id and angent_id only once here,
before the while loop, because the values are all the same */
while ($row = pg_fetch_array($sql_res)){
echo $order_number;
}
Assume broker and agent id numbers are each the same in every row. I don't want to echo them every time in the loop. I just want them to echo one time before the loop. Since they are the same, it does not matter which row they are echoed from.
I figured out a different way for a means to an end. It works well.
$sql = "SELECT
o.order_id, o.order_number, o.broker_id, o.agent_id
FROM orders o";
$sql_res = safe_query($sql);
$count = 0;
while ($row = pg_fetch_array($sql_res)){
if ($count == 0) {
echo $broker_id;
echo $agent_id;
}
echo $order_number;
$count += 1;
}
I realize I'm echoing the broker and agent IDs inside the while loop, but it's only an echo the first time through, and I can display them at top. And then every unique order is echoed. Visually, it accomplished what was needed for the end user.
I am running a while loop in PHP selecting data from a mysql database. How can i find out what the last record is,
for example:
$sql="SELECT * from table1 ";
$rs=mysql_query($sql,$conn);
while($result=mysql_fetch_array($rs))
{
echo $result["col1"].' - '.$result["col2"].'<br>';
}
then when it gets to the last record i want to display it like:
echo 'Last Record: '.$result["col1"].' - '.$result["col2"].'<br>';
You basically need to record how many rows you have, and then set up a counter. You can do that using mysql_num_rows():
$sql="SELECT * from table1";
$rs = mysql_query($sql,$conn);
$numRows = mysql_num_rows($rs);
$i = 1;
while($result=mysql_fetch_array($rs))
{
echo ($i == $numRows) ? 'Last Record: '.$result["col1"].' - '.$result["col2"].'<br />' : $result["col1"].' - '.$result["col2"].'<br />';
$i++;
}
You should note though that the mysql_*() family of functions is now deprecated. For security and longevity, you really ought to be using MySQLi or PDO.
Get the total count of rows returned and check use a flag variable for the loop iterations and check in loop if flag == total rows
$t=mysql_num_row($rs);
$i=0;
while($result=mysql_fetch_array($rs))
{
$i++;
if($t == $i){
echo "Last Record ";
}
echo $result["col1"].' - '.$result["col2"].'<br>';
}
mysql_num_rows
You can simply use the sql query itself to get the last value, based on whatever ordering you want (or just use DESC to get the bottom of the natural order):
SELECT * FROM table1
ORDER BY your_column DESC
LIMIT 1;
Edit: Since you're looking for the last row, you could check with mysql_num_rows
$numrows = mysql_num_rows($rs);
$i = 1;
// in while loop...
if ($i === $numrows) {
// print last result
} else {
// print normal result
}
$i++;
// end while loop
Essentially, you want a counter for the record you are on and then write when the number of rows is the same as the row number you are on (e.g. the last one)
$sql="SELECT * from table1 ";
$rs=mysql_query($sql,$conn);
$num_rows = mysql_num_rows ($rs);
for ($i=0; $i < $num_rows; $i++) {
$result=mysql_fetch_array($rs);
if ($i == ($num_rows - 1)) {
echo 'Last Record: '.$result["col1"].' - '.$result["col2"].'<br>';
} else {
echo $result["col1"].' - '.$result["col2"].'<br>';
}
}
Future-proof this routine by doing it the "hard way":
while ($next_row = fetch_row(...)) {
if ($prev_row) { do_output($prev_row); }
$prev_row = $next_row;
}
if ($prev_row) { do_output($prev_row, FLAG_IS_LAST_ROW); }
Why? Future maintenance might make mysql_num_rows() unreliable, either because your result set gets too big, or because you want to interface with a variety of SQL backends.
By default, the MySQL client library pulls the entire result set into memory — that is how it knows the number of rows SELECTed without having to count fetches. This behavior is rather convenient for small result sets, but devastating for large result sets. This it is user-configurable. (The options are usually named something like "store_result v. use_result" or "buffered v. unbuffered.")
Additionally, most RDBMS interfaces do not make the size of the result set known in advance. If you want to interface with these some day in a reusable way, you'll need to change your approach.
I have a game script thing set up, and when it creates a new character I want it to find an empty address for that players house.
The two relevant table fields it inserts are 'city' and 'number'. The 'city' is a random number out of 10, and the 'number' can be 1-250.
What it needs to do though is make sure there's not already an entry with the 2 random numbers it finds in the 'HOUSES' table, and if there is, then change the numbers. Repeat until it finds an 'address' not in use, then insert it.
I have a method set up to do this, but I know it's shoddy- there's probably some more logical and easier way. Any ideas?
UPDATE
Here's my current code:
$found = 0;
while ($found == 0) {
$num = (rand()%250)+1; $city = (rand()%10)+1;
$sql_result2 = mysql_query("SELECT * FROM houses WHERE city='$city' AND number='$num'", $db);
if (mysql_num_rows($sql_result2) == 0) { $found = 1; }
}
You can either do this in PHP as you do or by using a MySQL trigger.
If you stick to the PHP way, then instead of generating a number every time, do something like this
$found = 0;
$cityarr = array();
$numberarr = array();
//create the cityarr
for($i=1; $i<=10;$i++)
$cityarr[] = i;
//create the numberarr
for($i=1; $i<=250;$i++)
$numberarr[] = i;
//shuffle the arrays
shuffle($cityarr);
shuffle($numberarr);
//iterate until you find n unused one
foreach($cityarr as $city) {
foreach($numberarr as $num) {
$sql_result2 = mysql_query("SELECT * FROM houses
WHERE city='$city' AND number='$num'", $db);
if (mysql_num_rows($sql_result2) == 0) {
$found = 1;
break;
}
}
if($found) break;
}
this way you don't check the same value more than once, and you still check randomly.
But you should really consider fetching all your records before the loops, so you only have one query. That would also increase the performance a lot.
like
$taken = array();
for($i=1; $i<=10;$i++)
$taken[i] = array();
$records = mysql_query("SELECT * FROM houses", $db);
while($rec = mysql_fetch_assoc($records)) {
$taken[$rec['city']][] = $rec['number'];
}
for($i=1; $i<=10;$i++)
$cityarr[] = i;
for($i=1; $i<=250;$i++)
$numberarr[] = i;
foreach($cityarr as $city) {
foreach($numberarr as $num) {
if(in_array($num, $taken[]) {
$cityNotTaken = $city;
$numberNotTaken = $number;
$found = 1;
break;
}
}
if($found) break;
}
echo 'City ' . $cityNotTaken . ' number ' . $numberNotTaken . ' is not taken!';
I would go with this method :-)
Doing it the way you say can cause problems when there is only a couple (or even 1 left). It could take ages for the script to find an empty house.
What I recommend doing is insert all 2500 records in the database (combo 1-10 with 1-250) and mark with it if it's empty or not (or create a combo table with user <> house) and match it on that.
With MySQL you can select a random entry from the database witch is empty within no-time!
Because it's only 2500 records, you can do ORDER BY RAND() LIMIT 1 to get a random row. I don't recommend this when you have much more records.
I am trying to create a class registration system for a client that utilizes PHP and MySQL. I have the database and table all set up and that part works just fine, however, the client has requested that upon registration, if there are 3 or fewer students enrolled to warn that the class may not run.
I'm trying to use the count() function as well as passing a dynamic variable from a cookie, set from the registration PHP script. However, I've hit a roadblock. I can't seem to get the count() function to actually count the rows. My select statement is below. Any help would be greatly appreciated.
$class = $_COOKIE["class"];
$min_check = "SELECT class_list, COUNT(class_list) as count
FROM T_Student WHERE class_list = '$class'
GROUP BY class_list
HAVING count < 20";
$result = mysql_query($min_check);
$count = mysql_num_rows($result);
if ($count < 4)
{
echo "IF THERE ARE 3 OR FEWER PEOPLE SIGNED UP FOR THIS CLASS, IT MAY NOT RUN.\n";
echo "THERE ARE CURRENTLY " . $count . " PEOPLE SIGNED UP.\n";
}
else if ($count > 4)
{
echo "There are currently " . $count . " people signed up for this class.";
}
?>
Your SQL query is returning a list of the class_list values, along with a count of each specific instance, where there are less than 20 people registered.
$count = mysql_num_rows($result);
...is getting the number of records returned in the resultset, not the alias count value, which is why you aren't seeing the output you expect. You need to read into your resultset to get the value:
while ($row = mysql_fetch_assoc($result)) {
$count = $row['count'];
if($count < 4) { ... }
}
The count that you want is returned in the row of the query. the mysql_num_rows will count the rows returned, which is not what you want. Use this instead.
$result = mysql_query($min_check);
$count = mysql_fetch_row($result);
$count = $count[0];
On a first glance, the HAVING count < 20 is unnecessary.
You use the MySQL-count-function, but never retrieve it's value!? Use:
$firstRow = mysql_fetch_row($result);
$count = $firstRow[1]; // 1 indicates the second column (0 being the first)
I don't recommend using known MySQL identifiers like count. It's confusing.
$class = mysql_real_escape_string($_COOKIE["class"]);
$min_check = "SELECT class_list, COUNT(class_list) as mycount
FROM T_Student WHERE class_list = '$class'
GROUP BY class_list
HAVING mycount < 20";
Don't forget to escape the contents of that cookie!
The error is that count is a reserved word. You need to either surround it in backticks `count` or even better, use a different moniker. It's not an error per se, but it's just too confusing.
Next up, you are not actually retrieving the mycount result from the database. I suggest using code something like this:
$result = mysql_query($min_check);
while( $row = mysql_fetch_assoc($result) ) {
$people_count = $row['mycount'];
if ($people_count < 4) { echo "this" }
else { echo "that" }
}