I have the following code, sorry for the length but it saves explaining most of what i need...
the $result in the pages() function is not being returned. When I call for it all I get is undefined variable. Why?
What i need is to pass the $start and $display variables to the mysql query.
<?php
if(isset($_POST['get_records_submit'])) {
$pages; $start; $display; $result;
function pages($stmt) {
//set how many records per page
$display = 10;
//determine how many pages there are
if(isset($_GET['p']) && is_numeric($_GET['p'])) { //already determined
$pages = $_GET['p'];
}
else {
$records = mysqli_stmt_num_rows($stmt);
}
//calculate the number of pages
if($records > $display) { //if there are more records than will fit on one page
$pages = ceil($records/$display); //ceil() rounds up to the nearest integer
}
else { //records will fit on one page
$pages = 1;
}
//determine which row to start returning results from
if(isset($_GET['s']) && is_numeric($_GET['S'])) { //already determined
$start = $_GET['s'];
}
else {
$start = 0;
}
$result = array(0=>$display, 1=>$pages , 2=>$start);
return $result;
}
$searchby = $_POST['search_by'];
$searchfor = $_POST['search_for'];
$contact = 1;
$i = 0;
//set the initial query
$query = "SELECT client_id, title_desc, firstname, surname, house, street, town, city, county, postcode as count FROM address LEFT JOIN client USING (client_id) LEFT JOIN client_title USING (title_id) LEFT JOIN address_street USING (address_id) LEFT JOIN address_town USING (address_id) LEFT JOIN address_city USING (address_id) LEFT JOIN address_county USING (address_id) WHERE is_contact = ?";
//depending on search terms, amend the query
if($searchby == 'all') {
$query .= " ORDER BY surname ASC, firstname ASC";
$stmt = mysqli_prepare($dbc, $query);
mysqli_stmt_bind_param($stmt, 'i', $contact);
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
pages($stmt);
var_dump ($result);
foreach ($result as $var) { echo $var.' ';}
mysqli_stmt_close($stmt);
$query .= " ORDER BY surname ASC, firstname ASC LIMIT ?, ?";
$stmt = mysqli_prepare($dbc, $query);
mysqli_stmt_bind_param($stmt, 'iii', $contact, $start, $display);
mysqli_stmt_execute($stmt);
mysqli_stmt_bind_result($stmt, $client_id, $stitle, $sfname, $ssname, $shouse,$sstreet, $stown, $scity, $scounty, $spostcode);
if($searchfor != '') {
echo "<p>You searched under <span class=\"bold\">\"All\"</span>, therefore your search term <span class=\"bold\">\"$searchfor\"</span> has not been included.</p>";
}
}
}
In this line:
pages($stmt);
The function pages() returns the array, but this result is not being set to a variable. Try using:
$result = pages($stmt);
And then accessing the array via the variable $result.
That $result variable that you declared up top? The reason it's not being set is because the function pages() doesn't have access to it because it's not within the function's scope.
Edit
As Lyth pointed out, if you don't want the function to return anything, you can modify your function as follows:
function pages($stmt) {
global $result;
// ...
// The rest of your function
// ...
$result = array(0=>$display, 1=>$pages , 2=>$start);
// Remove the 'return $result' line
}
I do not know why you write $pages; $start; $display; $result;? If you want to get the value of array try to use this...
$result = array($display, $pages , $start);
return $result;
You can check the array with
print_r ($result);
Related
This is my code
public function count_er($str_arr){
for($i=0;$i<=count($str_arr);$i++){
$counter=("SELECT COUNT(*) FROM `number` where `group_id`='$str_arr[$i]'");
$q = mysqli_query($this->con,$counter);
$row .= $q->fetch_row();
}
return $row[0];
mysqli_close($this>con);
}
}
You're better off using a single query, and using a prepared statement. Then loop over all the results and store them in an array, which you return.
public function count_er(array $str_arr) {
$result = [];
$query = "SELECT group_id, COUNT(*)
FROM `number`
WHERE `group_id` IN (".trim(str_repeat("?,", count($str_arr)), ',').")
GROUP BY `group_id`";
$stmt = $this->con->prepare($query);
// "i" for integers, "s" for strings
$stmt->bind_param(str_repeat("i", count($str_arr)), ...$str_arr);
$stmt->execute();
$stmt->bind_param($group_id, $count);
while ($stmt->fetch()) {
$result[$group_id] = $count;
}
$stmt->close();
return $result;
}
I have created the following function to fetch data from my database, but its capabilities are limited. Currently it can fetch one value at a time, which is fine for fetching the value of one column of one row, but as I progress with my work, I now want to be able to fetch multiple values in one call.
The Function:
function retrieve($value, $identifier = null) {
// Check if identifier is given
$identifier = (is_null($identifier)) ? "`ID` = '{$_SESSION["ID"]}'" : $identifier;
// Connect to the database
$connection = connect("limited");
// Pass query, get result and fetch value out of it
$query = "SELECT * FROM `users` WHERE $identifier";
$result = mysqli_query($connection, $query);
if (mysqli_num_rows($result) > 0) {
$data = mysqli_fetch_assoc($result);
return $data[$value];
}
mysqli_close($connection);
}
How I currently use it to fetch multiple values:
// Define variables
$x1 = retrieve("x1");
$x2 = retrieve("x2");
$x3 = retrieve("x3");
$x4 = retrieve("x4");
$x5 = retrieve("x5");
$x6 = retrieve("x6");
$x7 = retrieve("x7");
$x7 = retrieve("x8");
I have read other questions here on Stack Overflow, but none of them solves my problem as I use an optional parameter, which makes my life hard. For example, I thought of implementing the splat operator to allow unlimited parameters, but as I use the optional parameter $identifier, I can't make it into something like:
function retrieve($identifier = null, ...$value) {}
because it will use the first parameter as the identifier when I omit it.
I'm sure that regarding performance it would be better if I could fetch all the necessary values in one call of the function retrieve() instead of using it as shown above and that's why I would like to know:
How can I edit this function in order to fetch more values at once?
Calling it like so:
$x = retrieve($y);
$x1 = $y["x1"];
$x2 = $y["x2"];
...
EDIT:
Thanks to Manish Jesani for his help! I used his answer and modified to do exactly what I want. For anyone that may be interested in the future, here's the code:
function retrieve($value, $identifier = null) {
// Check if identifier is given
$values = array();
$identifier = (is_null($identifier)) ? "`ID` = '1'" : $identifier;
// Connect to the database
$connection = connect("limited");
// Pass query, get result and fetch value out of it
$query = "SELECT * FROM `users` WHERE $identifier";
$result = mysqli_query($connection, $query);
if (mysqli_num_rows($result) > 0) {
$data = mysqli_fetch_assoc($result);
if (is_array($value)) {
foreach($value as $_value) {
$values[$_value] = $data[$_value];
}
return $values;
}
else {
return $data[$value];
}
}
mysqli_close($connection);
}
You can call the function with as many parameters you want. Τo do this you have to use func_num_args() to get all of them, as shown below:
function retrieve() {
$args = func_num_args();
$query = "SELECT '".implode("','", func_get_args())."' FROM `users` WHERE $identifier";
$result = mysqli_query($connection, $query);
if (mysqli_num_rows($result) > 0) {
$data = mysqli_fetch_assoc($result);
return $data;
}
mysqli_close($connection);
}
You can call this function like this: $params = retrieve('x1','x2','x3').
Alternatively, you can retrieve them as variables list($x1, $x2, $x3) = retrieve('x1','x2','x3').
Please try this:
function retrieve($value, $identifier = null) {
// Check if identifier is given
$return = array();
$identifier = (is_null($identifier)) ? "`ID` = '{$_SESSION["ID"]}'" : $identifier;
// Connect to the database
$connection = connect("limited");
// Pass query, get result and fetch value out of it
$query = "SELECT * FROM `users` WHERE $identifier";
$result = mysqli_query($connection, $query);
if (mysqli_num_rows($result) > 0) {
$data = mysqli_fetch_assoc($result);
if(is_array($value))
{
foreach($value as $_value)
{
$return[$_value] = $data[$_value];
}
}
else
{
$return[$value] = $data[$value];
}
return $return;
}
mysqli_close($connection);
}
$x = retrieve(array("x1","x2","x3","x4","x5","x6"));
I have this function which returns only one row, How can I modify the function so that it returns more than one row?
public function getVisitors($UserID)
{
$returnValue = array();
$sql = "select * from udtVisitors WHERE UserID = '".$UserID. "'";
$result = $this->conn->query($sql);
if ($result != null && (mysqli_num_rows($result) >= 1)) {
$row = $result->fetch_array(MYSQLI_ASSOC);
if (!empty($row)) {
$returnValue = $row;
}
}
return $returnValue;
}
There is a function in mysqli to do so, called fetch_all(), so, to answer your question literally, it would be
public function getVisitors($UserID)
{
$sql = "select * from udtVisitors WHERE UserID = ".intval($UserID);
return $this->conn->query($sql)->fetch_all();
}
However, this would not be right because you aren't using prepared statements. So the proper function would be like
public function getVisitors($UserID)
{
$sql = "select * from udtVisitors WHERE UserID = ?";
$stmt = $mysqli->prepare($sql);
$stmt->bind_param("s", $UserID);
$stmt->execute();
$res = $stmt->get_result();
return $res->fetch_all();
}
I would suggest storing them in an associative array:
$returnValue = array();
while($row = mysqli_fetch_array($result)){
$returnValue[] = array('column1' => $row['column1'], 'column2' => $row['column2']); /* JUST REPLACE NECESSARY COLUMN NAME AND PREFERRED NAME FOR ITS ASSOCIATION WITH THE VALUE */
} /* END OF LOOP */
return $returnValue;
When you call the returned value, you can do something like:
echo $returnValue[0]['column1']; /* CALL THE column1 ON THE FIRST SET OF ARRAY */
echo $returnValue[3]['column2']; /* CALL THE column2 ON THE FOURTH SET OF ARRAY */
You can still call all the values using a loop.
$counter = count($returnValue);
for($x = 0; $x < $counter; $x++){
echo '<br>'.$rowy[$x]['column1'].' - '.$rowy[$x]['column2'];
}
This question already has an answer here:
How to check fetched result set is empty or not?
(1 answer)
Closed 11 months ago.
What am I doing wrong here? I'm simply retrieving results from a table and then adding them to an array. Everything works as expected until I check for an empty result...
This gets the match, adds it to my array and echoes the result as expected:
$today = date('Y-m-d', strtotime('now'));
$sth = $db->prepare("SELECT id_email FROM db WHERE hardcopy = '1' AND hardcopy_date <= :today AND hardcopy_sent = '0' ORDER BY id_email ASC");
$sth->bindParam(':today', $today, PDO::PARAM_STR);
if(!$sth->execute()) {
$db = null;
exit();
}
while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
$this->id_email[] = $row['id_email'];
echo $row['id_email'];
}
$db = null;
return true;
When I try to check for an empty result, my code returns 'empty', but no longer yields the matching result:
$today = date('Y-m-d', strtotime('now'));
$sth = $db->prepare("SELECT id_email FROM db WHERE hardcopy = '1' AND hardcopy_date <= :today AND hardcopy_sent = '0' ORDER BY id_email ASC");
$sth->bindParam(':today',$today, PDO::PARAM_STR);
if(!$sth->execute()) {
$db = null;
exit();
}
if ($sth->fetchColumn()) {
echo 'not empty';
while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
$this->id_email[] = $row['id_email'];
echo $row['id_email'];
}
$db = null;
return true;
}
echo 'empty';
$db = null;
return false;
You're throwing away a result row when you do $sth->fetchColumn(). That's not how you check if there are any results. You do
if ($sth->rowCount() > 0) {
... got results ...
} else {
echo 'nothing';
}
Relevant documentation is here: PDOStatement::rowCount
If you have the option of using fetchAll() then, if there are no rows returned, it will just be an empty array.
count($sql->fetchAll(PDO::FETCH_ASSOC))
will return the number of rows returned.
You should not use rowCount for SELECT statements as it is not portable. I use the isset function to test if a select statement worked:
$today = date('Y-m-d', strtotime('now'));
$sth = $db->prepare("SELECT id_email FROM db WHERE hardcopy = '1' AND hardcopy_date <= :today AND hardcopy_sent = '0' ORDER BY id_email ASC");
// I would usually put this all in a try/catch block, but I kept it the same for continuity
if(!$sth->execute(array(':today'=>$today)))
{
$db = null;
exit();
}
$result = $sth->fetch(PDO::FETCH_OBJ)
if(!isset($result->id_email))
{
echo "empty";
}
else
{
echo "not empty, value is $result->id_email";
}
$db = null;
Of course this is only for a single result, as you might have when looping over a dataset.
I thought I would weigh in as I had to deal with this lately.
$sql = $dbh->prepare("SELECT * from member WHERE member_email = '$username' AND member_password = '$password'");
$sql->execute();
$fetch = $sql->fetch(PDO::FETCH_ASSOC);
// if not empty result
if (is_array($fetch)) {
$_SESSION["userMember"] = $fetch["username"];
$_SESSION["password"] = $fetch["password"];
echo 'yes this member is registered';
}else {
echo 'empty result!';
}
what I'm doing wrong here?
Almost everything.
$today = date('Y-m-d'); // no need for strtotime
$sth = $db->prepare("SELECT id_email FROM db WHERE hardcopy = '1' AND hardcopy_date <= :today AND hardcopy_sent = '0' ORDER BY id_email ASC");
$sth->bindParam(':today',$today); // no need for PDO::PARAM_STR
$sth->execute(); // no need for if
$this->id_email = $sth->fetchAll(PDO::FETCH_COLUMN); // no need for while
return count($this->id_email); // no need for the everything else
Effectively, you always have your fetched data (in this case in $this->id_email variable) to tell whether your query returned anything or not. Read more in my article on PDO.
One more approach to consider:
When I build an HTML table or other database-dependent content (usually via an AJAX call), I like to check if the SELECT query returned any data before working on any markup. If there is no data, I simply return "No data found..." or something to that effect. If there is data, then go forward, build the headers and loop through the content, etc. Even though I will likely limit my database to MySQL, I prefer to write portable code, so rowCount() is out. Instead, check the the column count. A query that returns no rows also returns no columns.
$stmt->execute();
$cols = $stmt->columnCount(); // no columns == no result set
if ($cols > 0) {
// non-repetitive markup code here
while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
I only found one way that worked...
$quote = $pdomodel->executeQuery("SELECT * FROM MyTable");
//if (!is_array($quote)) { didn't work
//if (!isset($quote)) { didn't work
if (count($quote) == 0) { //yep the count worked.
echo 'Record does not exist.';
die;
}
Thanks to Marc B's help, here's what worked for me (note: Marc's rowCount() suggestion could work too, but I wasn't comfortable with the possibility of it not working on a different database or if something changed in mine... also, his select count(*) suggestion would work too, but, I figured because I'd end up getting the data if it existed anyway, so I went this way).
$today = date('Y-m-d', strtotime('now'));
$sth = $db->prepare("SELECT id_email FROM db WHERE hardcopy = '1' AND hardcopy_date <= :today AND hardcopy_sent = '0' ORDER BY id_email ASC");
$sth->bindParam(':today', $today, PDO::PARAM_STR);
if(!$sth->execute()) {
$db = null;
exit();
}
while ($row = $sth->fetch(PDO::FETCH_ASSOC)) {
$this->id_email[] = $row['id_email'];
echo $row['id_email'];
}
$db = null;
if (count($this->id_email) > 0) {
echo 'not empty';
return true;
}
echo 'empty';
return false;
The following code needs to make use of 3 variables given by the user. By default all of these variables equal to 0.
time (textbox)
city (drop down list)
type (drop down list)
If for example time and city is given by the user, but lets the type zero, it will not return any results.
My question is what is an effective and efficient way to modify my existing code so that if the user chooses not to select time, city or type or any combination of these, there will be results returned?
For example if time 21:00 is added with city number 3, it will show all the types that meet the 2 criteria should be listed.
$question= 'SELECT * FROM events WHERE ABS(TIMESTAMPDIFF( HOUR , `time`, :time )) < 2 AND city=:city AND type=:type';
$query = $db->prepare($question);
$query->bindValue(":time", $time, PDO::PARAM_INT);
$query->bindValue(":city", $city, PDO::PARAM_INT);
$query->bindValue(":type", $type, PDO::PARAM_INT);
$query->execute();
<?php
$question= 'SELECT * FROM events WHERE ';
$hasTime = false;
if(!empty($time)) { // #note better validation here
$hasTime = true;
$question .= 'ABS(TIMESTAMPDIFF( HOUR , `time`, :time )) < 2 ';
}
$hasCity = false;
if(!empty($city)) { // #note better validation here
$hasCity = true;
$question .= 'AND city=:city ';
}
$hasType = false;
if(!empty($type)) { // #note better validation here
$hasType = true;
$question .= 'AND type=:type';
}
$query = $db->prepare($question);
if($hasTime)
$query->bindValue(":time", $time, PDO::PARAM_INT);
if($hasCity)
$query->bindValue(":city", $city, PDO::PARAM_INT);
if($hasType)
$query->bindValue(":type", $type, PDO::PARAM_INT);
$query->execute();
$results = $query->fetchAll();
if(empty($results))
echo 'no results';
else
// $results is an array of arrays
I prefer using an array of conditions, and checking through to see if the conditions exist, to built the individual parts of the SQL query:
$conditions = array(); // Creating an array of conditions.
if ($time) // Checks to see if value exists.
{
$timeCondition = "ABS(TIMESTAMPDIFF( HOUR , `time`, :time )) < 2";
$conditions[] = $timeCondition; // Adds this condition string to the array.
}
if ($city)
{
$cityCondition = "city=:city";
$conditions[] = $cityCondition;
}
if ($type)
{
$typeCondition = "type=:type";
$conditions[] = $typeCondition;
}
$conditionString = implode(" AND ", $conditions); // Gluing the values of the array with " AND " in between the string conditions.
if (count($conditions) > 0) // If conditions exist, add "WHERE " to the condition string.
{
$conditionString = "WHERE ".$conditionString;
}
else // Otherwise, the condition string is blank by default.
{
$conditionString = '';
}
$question= 'SELECT * FROM events '.$conditionString; // If no conditions, will return all from events. Otherwise, conditions will be slotted in through $conditionString.
$query = $db->prepare($question);
if($time)
$query->bindValue(":time", $time, PDO::PARAM_INT);
if($city)
$query->bindValue(":city", $city, PDO::PARAM_INT);
if($type)
$query->bindValue(":type", $type, PDO::PARAM_INT);
$query->execute();
You can use a series of IF() statements in your SQL statement, and return true if the value isn't set. So something like this:
...WHERE IF(:time, ABS(TIMESTAMPDIFF(HOUR, `time`, :time)) < 2, 1)
AND IF(:city, city=:city, 1) AND IF(:type, type=:type, 1)
Build the query dynamically so that if the field is at its default, do not include it in the where clause.
$conditions = array();
if ($_POST['time']) {
$conditions[] = "ABS(TIMESTAMPDIFF( HOUR , `time`, :time )) < 2";
}
if ($_POST['city']) {
$conditions[] = "city=:city";
}
if ($_POST['type']) {
$conditions[] = "type=:type";
}
$conditionString = implode(" AND ", $conditions);
if (count($conditions) > 0) {
$conditionString = "WHERE " . $conditionString;
}
else {
$conditionString = '';
}
$question = 'SELECT * FROM events ' . $conditionString;