Background: I have an array created by:
$order = $_POST['order'];
The contents only have a single value per row:
[0] => 1
[1] => 4
[2] => 5
[3] => 2
[4] => 2
I am updating a database with this:
for ($i=0; $i<count($order); $i++)
{
$sql = "UPDATE catalog SET quantity=quantity - $order[$i] WHERE item_number= $i +1";
$result = mysqli_query($connection,$sql) or
die("<b>Query Failed.</b><br>" . mysqli_error($connection));
}
But I would like to use SELECT to search for records in which I have updated. Of course the problem is I do not have a direct item number to reference since I used $i +1 to refer to it.
As you can see the (array)key+1 to each value is equal to the item_number. So I was hoping to create an array in which the following is true:
for ($i=0; $i<count($order); $i++)
{
if ($order[$i] > 0)
{
$itemNum[$i] = 1;
} else {
$itemNum[$i] = 0;
}
I am sure I am over thinking this but I just need to be able to set up a WHERE statement displaying only item_num records which were just updated.
Make an array containing all the item_numbers you are updating. Then, select those item_numbers.
$updated = [];
for ($i=0; $i<count($order); $i++)
{
if ($order[$i] > 0) {
$updated[] = $i + 1;
$sql = "UPDATE catalog SET quantity=quantity - $order[$i] WHERE item_number= $i +1";
$result = mysqli_query($connection,$sql) or
die("<b>Query Failed.</b><br>" . mysqli_error($connection));
}
}
$sql = "SELECT * FROM catalog WHERE item_number IN (" . implode(",", $updated) . ")";
What are you going to do if the order is for more quantity than are remaining in catalog?
Related
I'm looking to insert random numbers into each column in a database.
The issue that is occuring is that each column for some reason has the same random generated value being passed inside.
$sql = "SELECT * FROM players";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// output data of each row
$targScore = 3;
while($row = $result->fetch_assoc()) {
$target = 3; // The target number the sequence is adding up to
$n = 4; // Max numbers within sequence
while ($n) {
if (1 < $n--) {
$addend = rand(0, $target - ($n - 1));
$target -= $addend;
$num[] = $addend;
} else {
$num[] = $target;
}
}
/* Rows to update */
/* Output looks like:
[0] = 1
[1] = 2
[0] = 0
[0] = 1
*/
$changeScore = "UPDATE players SET doja='$num[0]' WHERE score='$targScore'";
$conn->query($changeScore);
$changeScore = "UPDATE players SET 7acres='$num[1]' WHERE score='$targScore'";
$conn->query($changeScore);
$changeScore = "UPDATE players SET tweed='$num[2]' WHERE score='$targScore'";
$conn->query($changeScore);
$changeScore = "UPDATE players SET bickel='$num[3]' WHERE score='$targScore'";
$conn->query($changeScore);
}
}
The data looks like: https://imgur.com/a/nhhZDVo
What I need is that each loop, it will run the randomizer again but change the numbers its inserting so that each row will have different numbers.
You need to first get a list of all the rows that meet the score condition. Then you have to update them one by one, so you can set different random values in each.
$select_stmt = $conn->prepare("SELECT id FROM players WHERE score = ?");
$select_stmt->bind_param("i", $targScore);
$select_stmt->execute();
$res = $select_stmt->get_result();
$update_stmt = $conn->prepare("UPDATE players SET doja = ?, 7acres = ?, tweed = ?, bickel = ? WHERE id = ?");
$update_stmt->bind_param("iiiii", $doja, $acres, $tweed, $bickel, $id);
$target = 3;
while ($row = $res->fetch_assoc()) {
$n = 4;
$num = [];
while ($n) {
if (1 < $n--) {
$addend = rand(0, $target - ($n - 1));
$target -= $addend;
$num[] = $addend;
} else {
$num[] = $target;
}
}
[$doja, $acres, $tweed, $bickel] = $num;
$id = $row['id'];
$update_stmt->execute();
}
There's also no need to use four UPDATE statements to update 4 columns in the same rows.
MySQL has a rand() function https://dev.mysql.com/doc/refman/5.7/en/mathematical-functions.html#function_rand
(Note the warning that it's not perfectly random / security secure, but nor is PHPs rand()).
If you do not need to know what the values are, you can simply do UPDATE myCol=FLOOR(RAND() * 200) WHERE myConditionalField=MyCondition
This will allocate a random number from 0 to 199; examples in the MySQL manual (linked above) as to how to set a range, e.g. FLOOR(7 + (RAND() * 5)) gives an integer from 7 to 11.
I need to count the number of elements that exist in the column of a MySQL database row for multiple rows and them add them all together. This is the code I used to count the number of array elements (which are numbers separated by commas):
$result = substr_count($count_fetch['micro_analysis'], ",") + 1;
But now I need to do this for each row, which could vary depending on the query. I need to add the $result of each row together to get a final sum of all the rows. I used the following code but I get the incorrect value, can someone please point me in the right direction?
$sql = "SELECT * FROM samples_database WHERE order_id = $order_id";
$count_query = mysqli_query($conn, $sql);
$count_fetch = mysqli_fetch_assoc($count_query);
foreach ($count_fetch as $row) {
$result = substr_count($count_fetch['micro_analysis'], ",") + 1;
$end_result += $result;
}
echo $end_result;
You are just fetching 1 row and then trying to count over that row, instead you need to loop over the rows and add the fields in that...
$sql = "SELECT * FROM samples_database WHERE order_id = $order_id";
$end_result = 0;
$count_query = mysqli_query($conn, $sql);
while( $row = mysqli_fetch_assoc($count_query)) {
$end_result += substr_count($row['micro_analysis'], ",") + 1;
}
echo $end_result;
Replace your code with the following:
$sql = "SELECT * FROM samples_database WHERE order_id = $order_id";
$count_query = mysqli_query($conn, $sql);
$count_fetch = mysqli_fetch_assoc($count_query);
$end_result=0;//initialize variable to 0
foreach ($count_fetch as $k => $row) {
if($k == 'micro_analysis'){
$result = substr_count($row, ",") + 1; //change over here
$end_result += $result;
}
}
echo $end_result;
I am trying to make a selection based on a nested array I get from a prior selection.
Here is where I make my first selection:
$coursequery = "
SELECT
courseID
FROM enrollments
WHERE
studentID = '$userid'
";
try
{
$stmt = $db->prepare($coursequery);
$result = $stmt->execute();
}
catch(PDOException $ex)
{
die("Failed to run query: " . $ex->getMessage());
}
$rows = $stmt->fetchAll();
$_SESSION['studentcourses'] = $rows;
This gets all the courseID's in the following format:
Array ( [0] => Array ( [courseID] => 6 ) [1] => Array ( [courseID] => 7 ) )
and I want to be able to access these ID's for selecting information from a different table. I've started by trying to use a for loop to grab all the "course information" depending on the ID.
for($i = 0; $i < $count; $i++) {
$coursequery = "
SELECT
*
FROM courses
WHERE courseID = '$studentcourses[$i]'
";
try
{
$stmt = $db->prepare($coursequery);
$result = $stmt->execute();
}
catch(PDOException $ex)
{
die("Failed to run query: " . $ex->getMessage());
}
$row = $stmt->fetchAll();
$_SESSION['studentcourseinfo'] = $row;
}
Any help would be greatly appreciated in accomplishing this!
You can accomplish this with one SQL query thus eliminating all these loops
SELECT
*
FROM courses
INNER JOIN enrollments ON
enrollments.courseID = courses.courseID
AND enrollments.studentID = '$userid'
WHERE 1
you can use same array in query, can use implode function
$coursequery = "SELECT * FROM courses
WHERE courseID IN (" . implode(",", $studentcourses) . ");";
As long as you change the output format
Array (6, 7)
where 6 and 7 would be the id of the courses
Also in you code have mistake in rewrite var $_SESSION['studentcourseinfo'] = $row; these overwriting the same variable at a time
I'm trying to do a for loop inside a foreach loop.
I have a table in my database as follows:
ID | Fname | Lname
------------------------
1 Bart Simpson
1 Mickey Mouse
2 Peter Griffin
2 Clark Kenet
2 David Johnson
i call the data from the database (and it works, tested on phpmyadmin), I want the data to be shown on the page by the ID value for exemple:
Bart Simpson, Mickey Mouse & Peter Griffin
Clark Kenet & David Johnson
as you see there in an "&" before the last name at any row but that isnt my problem.
this is the code i wrote:
//HERE I RETRIVE ALL THE DATA FROM THE DATABASE.
$query = $dbh->query(" SELECT *
FROM table
WHERE ID= '{$ID}'
");
//THIS CODE SHOWS THE NUMBER OF ROWS WITH THE CURRENT ID
$sql = "SELECT COUNT( * ) FROM table WHERE ID= '{$ID}'";
$result = $dbh->prepare($sql);
$result->execute();
$number_of_rows = $result->fetchColumn();
//THIS IS THE FOREACH IN WHICH I CALL ALL THE ROWS BY THEIR VALUE
foreach ($query as $key =>$value) {
$value['wFname'][$key] = !empty($value['wFname'][$key]) ? $value['wFname'][$key] : '';
$numRow = $number_of_rows-2; // THE ITEM BEFORE THE LAST ONE IN THE ARRAY
$lastItem = $number_of_rows-1; //LAST INDEX IN THE ARRAY
for($counter = 0; $counter = $numRow; $counter++){
return $value['wLname'][$counter] . ', '. $value['wFname'][$counter];
}
return "&" . $value['wLname'][$lastItem] . ', '.$value['wFname'][$lastItem] ;
return ' ';
};
with this code i get only the first pair of names with each id.
any help would be great.
Try changing:
for($counter = 0; $counter = $numRow; $counter++){
to:
for($counter = 0; $counter =< $numRow; $counter++){
You are checking if $counter equals $numRow, and you should check if it equals and is less than...
Hope this helps.
EDIT Based on user requests
Try storing the results in a variable and return that variable at the end of both loops, but im not sure what you are trying to achieve here, try running the following code:
//HERE I RETRIVE ALL THE DATA FROM THE DATABASE.
$query = $dbh->query(" SELECT *
FROM table
WHERE ID= '{$ID}'
");
//THIS CODE SHOWS THE NUMBER OF ROWS WITH THE CURRENT ID
$sql = "SELECT COUNT( * ) FROM table WHERE ID= '{$ID}'";
$result = $dbh->prepare($sql);
$result->execute();
$number_of_rows = $result->fetchColumn();
//THIS IS THE FOREACH IN WHICH I CALL ALL THE ROWS BY THEIR VALUE
$return = "";
foreach ($query as $key => $value) {
$value['wFname'][$key] = !empty($value['wFname'][$key]) ? $value['wFname'][$key] : '';
$numRow = $number_of_rows - 2; // THE ITEM BEFORE THE LAST ONE IN THE ARRAY
$lastItem = $number_of_rows - 1; //LAST INDEX IN THE ARRAY
for ($counter = 0; $counter <= $numRow; $counter++) {
$return .= $value['wLname'][$counter] . ', ' . $value['wFname'][$counter];
}
$return .= "&" . $value['wLname'][$lastItem] . ', ' . $value['wFname'][$lastItem];
$return .= ' ';
}
return $return;
I have an array in PHP that is looping through a set of names (and a corresponding quantity). I would like to print the ones found in a MYSQL database table (to which I've succesfully connected). I'm currently using the code:
foreach ($arr as $name => $quan) {
$query = "SELECT * FROM table WHERE name='$name'";
$result = mysql_query($query) or die(mysql_error());
if (mysql_num_rows($result) > 0) {
$row = mysql_fetch_array($result);
echo $quan." ".$row['name']. "\n";
}
}
For some reason, this only prints the last quantity and name in the array. Help?
For example, if the array has key-value pairs of {A-4, B-2, C-3}, and table contains {A, B, D} as names ... it'll only print "2 B".
Change the code to the following:
foreach ($arr as $name => $quan) {
$query = "SELECT * FROM table WHERE name='$name'";
$result = mysql_query($query) or die(mysql_error());
if (mysql_num_rows($result) > 0) {
while($row = mysql_fetch_array($result)) {
echo $quan." ".$row['name']. "\n";
}
}
}
You have to loop through the result. By the way, stop using mysql_query()! use MySQLi or PDO instead ( and be careful of SQL Injection ; you can use mysqli_real_escape_string() to handle input parameters ). For MySQLi implementation , here it is :
foreach ($arr as $name => $quan) {
$query = "SELECT * FROM table WHERE name='$name'";
$result = mysqli_query($query) or die(mysqli_error());
if (mysqli_num_rows($result) > 0) {
while($row = mysqli_fetch_array($result)) {
echo $quan." ".$row['name']. PHP_EOL;
}
}
}
And rather "\n", I prefer using PHP_EOL ( as shown above )
And as the comment suggests, the SQL statement can be executed once, as follow:
$flipped_array = array_flip($arr); // flip the array to make "name" as values"
for($i = 0; $i < count($flipped_array); $i++) {
$flipped_array[$i] = '\'' . $flipped_array[$i] . '\''; // add surrounding single quotes
}
$name_list = implode(',', $arr);
$query = "SELECT * FROM table WHERE name IN ($name_list)";
// ... omit the followings
e.g. in $arr contains "peter", "mary", "ken", the Query will be:
SELECT * FROM table WHERE name IN ('peter','mary','ken')
sidenote: but I don't understand your query. You only obtain the name back from the query? You can check number of rows, or you can even group by name, such as:
SELECT name, COUNT(*) AS cnt FROM table GROUP BY name ORDER BY name
to get what you want.
UPDATE (again): based on the comment of OP, here is the solution :
$flipped_array = array_flip($arr); // flip the array to make "name" as values"
for($i = 0; $i < count($flipped_array); $i++) {
$flipped_array[$i] = '\'' . $flipped_array[$i] . '\''; // add surrounding single quotes
}
$name_list = implode(',', $arr);
$query = "SELECT name, COUNT(*) AS cnt FROM table WHERE name IN ($name_list) GROUP BY name HAVING COUNT(*) > 0 ORDER BY name";
$result = mysqli_query($query) or die(mysqli_error());
if (mysqli_num_rows($result) > 0) {
while($row = mysqli_fetch_array($result)) {
echo $quan." ".$row['name']. ": " . $row['cnt'] . PHP_EOL;
}
}
The above query will show the name appearing in the table only. Names not in table will not be shown. Now full codes ( be cautious of SQL Injection , again )