I have to identify unsaved value from mysql table using php and mysql, for example i using table named as numtab and i have already stored some numbers 1, 3, 4, 7, 23, 12, 45 in numb column.
now i have generated one new number randomly(for example 23) and i have to check this number with already stored numbers,
if 23 is exist in the table mean i have to generate another one new number and have to check once again with stored values, this process have to continue till finding unsaved number.
if generated value is not exist in table mean can stop the process and can store this number in table.
here below the format i am currently using
$numb=23;
$qryb="select * from numtab where numb='$numb'";
$results=mysql_query($qryb)or die("ERROR!!");
if(mysql_num_rows($results) == 1)
{
$numb=rand(1,100);
mysql_query("insert query");
}
the problem is above the code is validation once only, its not verifying second time. i think if using for or while loop mean can solve this problem, but i dont know how to do looping, so help me to solve this problem.
You can use in clause like this :
$qryb="select * from numtab where numb in('$numb')";
$results=mysql_query($qryb)or die("ERROR!!");
$count = mysql_num_rows($results);
if ($count > 0) {
echo "number exist in db";
} else {
echo "number does not exist in db";
}
You could make a while() loop to check if the numbers exist in your database. You could also retrieve all numbers from the database, store them in an array and check if the generated number exists within that array.
The first option would be something like this:
do {
$numb=rand(1,100);
$qryb="select * from numtab where numb='$numb'";
$results = mysql_query($qryb) or die("ERROR!!");
} while(mysql_num_rows($results) >= 1)
mysql_query("insert query");
The second option would be something like this:
$query = mysql_query("SELECT DISTINCT(numb) as numb FROM numtab");
// set array
$array = array();
// look through query
while($row = mysql_fetch_assoc($query)){
// add each row returned into an array
$array[] = $row['numb'];
}
do
{
$numb = rand(1,100);
}
while(!in_array ( $numb , $array) ;
mysql_query("insert query");
Related
I originally was satisfied with the following in order to update row 1 and row 2 to the same value (status=1)
if ($_POST){
$sql ="UPDATE table SET status = 1,
WHERE id IN (1,2 );";
db()->query($sql);
if(db()->query($sql)){
echo "<b>Good</b>";
}
else{
echo "<b>No Good</b>";
}
}
But now I want to update with different values, ie- row 1 to status 1, row 2 to status 2, and row 3 to status 3.
Off the bat, I know I need to
1. Use an array and loop through it three times.
2. pass in the array value into the $sql
I figure it would be something like this but I am still learning PHP..
$array_id = array(1, 2, 3);
$array_status = array(1, 2, 3);
if ($_POST){
$sql ="UPDATE table SET status = $array_status
WHERE id = $array_id;";
db()->query($sql);
if(db()->query($sql)){
echo "<b>Update Successful</b>";
}
else{
echo "<b>Update Unsuccessful</b>";
}
}
How would I go about making this happen?
You can loop through the arrays using a for loop and exec a query for each one (Radu Vlad answer), or you can build a long query and execute it once, something like this:
if ($_POST){
$sql = ""; // Blank string
$len = count($array_id); // Number of iterations
for ($i = 0; $i < $l; $i++) { // Enter the loop
$sql .= "UPDATE
table
SET
status = {$array_status[$i]}
WHERE id = {$array_id[$i]};"; // Append the query
}
db()->query($sql);
if(db()->query($sql)){
echo "<b>Update Successful</b>";
}
else{
echo "<b>Update Unsuccessful</b>";
}
}
When the val of $i is 0, then $array_id[$i] will print the first element, when $i is 1, $array_id[$i] will print the second element, and so on.
Using .= you append text to a string. By the end of the loop, $sql will be a string with 3 queries ('UPDATE ... SET ...; UPDATE ... SET ...; UPDATE ... SET ...;').
Not sure if it's the best way, though. But you get the idea.
If yow want the status to be equal to the id, do this (single query):
UPDATE table SET status=id WHERE id IN (1,2,3);
Of course you can use some math, like:
UPDATE table SET status=(id+1)*2 WHERE id IN (1,2,3);
You didn't really explain why you need that, so
try1(childish): set status = id
"UPDATE table SET status = id"
It's a bad practice, and only you could understand what those numbers are. Plus if id is auto-increment, status will be auto-increment too, you will have a duplicate column. If status has only 3 values posible, you should not do this.
try2(basic): do 3 updates, or actually, do as many as you need with a for
if ($_POST){
$status = 1;
for ($i = 1; $i <= 3; $i++){
$sql ="UPDATE table
SET status = $status
WHERE id = $i;";
db()->query($sql);
$status++;
}
A better way bacause you have more control over the status. Of course the second try is irrelevant if you have only that 3 values. This one assumes you will change the $status variable inside the for loop, in concordance with the $i (id)
try3(mature): set one or 2 arrays with the concordance between id and status, so that either $arr[$id] will have the value of status and the key will be the id, or $arr1[$i] will have the value of id, and $arr2[$i] will have the value of status
the example will have only one array(also called map, because you map a value based on another value)
if ($_POST){
$status_array = array(1 => 1,2 => 2,3 => 3);
for ($i = 1; $i <= 3; $i++){
$sql ="UPDATE table
SET status = $status_array[$i]
WHERE id = $i;";
db()->query($sql);
}
Also, this works because the array is consistent. If you do not have an consistent array you should either work with 2 arrays, or try a foreach with key->value instead of for
I would suggest you to use the following code:
$theArray = array("1" => "1","2" => "2","3" => "3"); // The scheme is ID => Status
$errorMsg = false; // Our default assumption is that no error occured
foreach($theArray as $key => $value) {
$sql = "UPDATE table SET status =".$value." WHERE id = ".$key;
if(!db() -> query($sql)) { // Execute the query and check whether it failed
$errorMsg = "Query for ID ".$key." failed.";
break; // When the query failed we exit the loop and echo the error message
}
}
if($errorMsg) { // If an error occured (errorMsg is no longer false) we echo it here
echo $errorMsg;
}
Basically you do just create one array $theArray, which contains key => value pairs of the IDs and the statuses you want to give them. Afterwards, you loop through this array, execute the db() -> query() for each key => value pair and check whether it failed or not. If a query failed, you break the loop and output the error message.
Advantages:
Instead of using two arrays ($array_id, $array_status) I do use only one associative array $theArray. The advantage here is that you only have one instead of two arrays and that you can extend the number of rows you'd like to change without changing your code. Just extend the array.
The array $theArray does not need to be in a chronological order and you can give each ID independently of the other IDs a status.
You are executing the db() -> query($sql) in your code two times. This is not very efficient and redundant. Instead you can execute the command only once and immediately check whether it failed or not based on its return value inside the if().
The errorMsg I am creating in the code let you know which query failed so it gives you a more detailed information for debugging.
If you want to update multiple rows (in single query) using the INSERT syntax, you can do this:
REPLACE table(id,status) VALUES(1,1),(2,2),(3,3)
Notice that id must be Primary Key or Unique, otherwise the REPLACE will insert a new row.
Notice also that REPLACE isn't SQL standard, and works only in MySQL.
I have a query like this:
$sql = "SELECT * FROM doctors WHERE city ='$city' LIMIT 10 ";
$result = $db->query($sql);
And I show the result like this :
while($row = $result->fetch_object()){
echo $row->city;
}
The Problem :
Mysql , will search through my database to find 10 rows which their city field is similar to $city.
so far it is OK;
But I want to know what is the exact row_number of the last result , which mysql selected and I echoed it ?
( I mean , consider with that query , Mysql selected 10 rows in my database
where row number are:
FIRST = 1
Second = 5
Third = 6
Forth = 7
Fifth = 40
Sixth = 41
Seventh = 42
Eitghth = 100
Ninth = 110
AND **last one = 111**
OK?
I want to know where is place of this "last one"????
)
MySQL databases do not have "row numbers". Rows in the database do not have an inherent order and thereby no "row number". If you select 10 rows from the database, then the last row's "number" is 10. If each row has a field with a primary id, then use that field as its "absolute row number".
You could let the loop run and track values. When the loop ends, you will have the last value. Like so:
while($row = $result->fetch_object()){
echo $row->city;
$last_city = $row->city;
}
/* use $last_city; */
To get the row number in the Original Table of the last resultant (here, tenth) row, you could save the data from the tenth row and then, do the following:
1. Read whole table
2. Loop through the records, checking them against the saved data
3. Break loop as soon as data found.
Like So:
while($row = $result->fetch_object()){
echo $row->city;
$last_row = $row;
}
Now, rerun the query without filters:
$sql = "SELECT * FROM doctors";
$result = $db->query($sql);
$rowNumber = 0;
while($row = $result->fetch_object()) {
if($row == $last_row) break;
$rowNumber++;
}
/* use $rowNumber */
Hope this helps.
What you can do is $last = $row->id; (or whatever field you want) inside your while loop - it will keep getting reassigned with the end result being that it contains the value of the last row.
You could do something like this:
$rowIndex = 0;
$rowCount = mysqli_num_rows($result);
You'd be starting a counter at zero and detecting the total number of records retrieved.
Then, as you step through the records, you could increment your counter.
while ( $row = $result->fetch_object() ) {
$rowIndex++;
[other code]
}
Inside the While Loop, you could check to see whether the rowIndex is equal to the rowCount, as in...
if ($rowIndex == $rowCount) {
[your code]
}
I know this is a year+ late, but I completely why Andy was asking his question. I frequently need to know this information. For instance, let's say you're using PHP to echo results in a nice HTML format. Obviously, you wouldn't need to know the record result index in the case of simply starting and ending a div, because you could start the div before the loop, and close it at the end. However, knowing where you are in the result set might affect some styling decisions (e.g., adding particular classes to the first and/or last rows).
I had one case in which I used a GROUP BY query and inserted each set of records into its own tabbed card. A user could click the tabs to display each set. I wanted to know when I was building the last tab, so that I could designate it as being selected (i.e., the one with the focus). The tab was already built by the time the loop ended, so I needed to know while inside of the loop (which was more efficient than using JavaScript to change the tab's properties after the fact).
I have this script:
$rrezervim_id = rand(1, 5);
$result = mysql_query("SELECT rrezervim_id FROM pax_list WHERE rrezervim_id='$rrezervim_id'");
if(mysql_num_rows($result) == 1)
{
$rrezervim_id = rand(1, 5);
}
else(mysql_num_rows($result) > 1);
{
echo "$rrezervim_id";
}
What i am trying to do is To generate a Unique Random number using PHP and MySql
i have the value inside table( rrezervim_id)[Values:1,2,3,5] so the only Random number that have to be generated and is free is Number 4.
But with this script something is not working since i am getting even random that are already inserted in the table [Values:1,2,3,5].
Any one can help me, is very important to make a check in mysql before generating the unique number if already exist in table.
First of all, the direct error in your code is
if(mysql_num_rows($result) == 1)
{
$rrezervim_id = rand(1, 5);
}
fails, if you hit a taken number twice. You need a loop, such as
while (mysql_num_rows($result) == 1)
{
$rrezervim_id = rand(1, 5);
$result = mysql_query("SELECT rrezervim_id FROM pax_list WHERE rrezervim_id='$rrezervim_id'");
}
That said, I suspect, that there is more wrong with your code:
If you want to use this "free" random number to insert it into the database at a later point in time, you are wide open to a race condition: Both processes select the same (still free) number, but only on the first insert is it still unique.
This approach can have extremely bad performance, if your field of possible random numbers is nearly full: If you have 80% fill rate, such as in your example, you will on average have 4 "bad" hits, before getting a "good" hit.
I recommend you consider using a database built-in, such as the battle-proven AUTO_INCREMENT as a primary means, then use a formula to create the hard-to-guess pseudo-random from it. A linear feedback shift register can be one approach, while cryptographically combining the auto-generated ID and a (not necessarily unique) pseudo-random stored in the table might be another. Both methods give you linear performance and race-free usage.
you can create unique number in php
<?php
echo uniqid();
?>
But you should use AUTO INCREMENT. If you want to know by which number inserted item is saved use something like this:
function insertUser(){
Global $userName;
$sqlInsert="INSERT INTO person (e_mail)
VALUES ('".$userName."')";
if (!mysql_query($sqlInsert)){
die('Error: ' . mysql_error());
}
$userId = mysql_insert_id();
return $userId;
}
in $userId is last inserted value
Since you are not using AUTO_INCREMENT, a suggestion (which is slow) is to select all the numbers that are valid and pick 1 randomly.
If we have [1,2,3,5,7] and our allowed elements are 1..10, then we have 5 allowed elements(4,6,8,9,10). So we rand(1,5). If we get "1", our next number is 4, if we get "2", our next number is 6. To better explain the idea:
Rand(1,5) Our array Value(available)
1
2
3
1 - 4
5
2 - 6
7
3 8
4 9
5 10
Code example:
$max_num = 100;
$res = mysql_query("SELECT rrezervim_id FROM pax_list ORDER BY rrezervim_id ASC");
$nums = [];
while($row = mysql_fetch_assoc($res)){
$nums[] = $res['rrezervim_id'];
}
$numbers_allowed = $max_num - count($nums); // actual number of allowed elements
$new_num_idx = rand(1, $numbers_allowed); // The selected element's index
(skipping all existing elements)
// in the following loop: $j starts as our lowest options.
// when $new_num_idx reaches 0 - it means that we have skipped
// over $new_num_idx elements. The next available element is
// our choice. $new_num_idx is a countdown
for($i=0,$j=1, $n=count($nums); $i<$n && $new_num_idx > 0; $i++){
while ($nums[$i]>$i+$j){
$j++; $new_num_idx--;
}
}
return $i+$j;
I previously designed the website I'm working on so that I'd just query the database for the information I needed per-page, but after implementing a feature that required every cell from every table on every page (oh boy), I realized for optimization purposes I should combine it into a single large database query and throw each table into an array, thus cutting down on SQL calls.
The problem comes in where I want this array to include skipped IDs (primary key) in the database. I'll try and avoid having missing rows/IDs of course, but I won't be managing this data and I want the system to be smart enough to account for any problems like this.
My method starts off simple enough:
//Run query
$localityResult = mysql_query("SELECT id,name FROM localities");
$localityMax = mysql_fetch_array(mysql_query("SELECT max(id) FROM localities"));
$localityMax = $localityMax[0];
//Assign table to array
for ($i=1;$i<$localityMax+1;$i++)
{
$row = mysql_fetch_assoc($localityResult);
$localityData["id"][$i] = $row["id"];
$localityData["name"][$i] = $row["name"];
}
//Output
for ($i=1;$i<$localityMax+1;$i++)
{
echo $i.". ";
echo $localityData["id"][$i]." - ";
echo $localityData["name"][$i];
echo "<br />\n";
}
Two notes:
Yes, I should probably move that $localityMax check to a PHP loop.
I'm intentionally skipping the first array key.
The problem here is that any missed key in the database isn't accounted for, so it ends up outputting like this (sample table):
1 - Tok
2 - Juneau
3 - Anchorage
4 - Nashville
7 - Chattanooga
8 - Memphis
-
-
I want to write "Error" or NULL or something when the row isn't found, then continue on without interrupting things. I've found I can check if $i is less than $row[$i] to see if the row was skipped, but I'm not sure how to correct it at that point.
I can provide more information or a sample database dump if needed. I've just been stuck on this problem for hours and hours, nothing I've tried is working. I would really appreciate your assistance, and general feedback if I'm making any terrible mistakes. Thank you!
Edit: I've solved it! First, iterate through the array to set a NULL value or "Error" message. Then, in the assignations, set $i to $row["id"] right after the mysql_fetch_assoc() call. The full code looks like this:
//Run query
$localityResult = mysql_query("SELECT id,name FROM localities");
$localityMax = mysql_fetch_array(mysql_query("SELECT max(id) FROM localities"));
$localityMax = $localityMax[0];
//Reset
for ($i=1;$i<$localityMax+1;$i++)
{
$localityData["id"][$i] = NULL;
$localityData["name"][$i] = "Error";
}
//Assign table to array
for ($i=1;$i<$localityMax+1;$i++)
{
$row = mysql_fetch_assoc($localityResult);
$i = $row["id"];
$localityData["id"][$i] = $row["id"];
$localityData["name"][$i] = $row["name"];
}
//Output
for ($i=1;$i<$localityMax+1;$i++)
{
echo $i.". ";
echo $localityData["id"][$i]." - ";
echo $localityData["name"][$i];
echo "<br />\n";
}
Thanks for the help all!
Primary keys must be unique in MySQL, so you would get a maximum of one possible blank ID since MySQL would not allow duplicate data to be inserted.
If you were working with a column that is not a primary or unique key, your query would need to be the only thing that would change:
SELECT id, name FROM localities WHERE id != "";
or
SELECT id, name FROM localities WHERE NOT ISNULL(id);
EDIT: Created a new answer based on clarification from OP.
If you have a numeric sequence that you want to keep unbroken, and there may be missing rows from the database table, you can use the following (simple) code to give you what you need. Using the same method, your $i = ... could actually be set to the first ID in the sequence from the DB if you don't want to start at ID: 1.
$result = mysql_query('SELECT id, name FROM localities ORDER BY id');
$data = array();
while ($row = mysql_fetch_assoc($result)) {
$data[(int) $row['id']] = array(
'id' => $row['id'],
'name' => $row['name'],
);
}
// This saves a query to the database and a second for loop.
end($data); // move the internal pointer to the end of the array
$max = key($data); // fetch the key of the item the internal pointer is set to
for ($i = 1; $i < $max + 1; $i++) {
if (!isset($data[$i])) {
$data[$i] = array(
'id' => NULL,
'name' => 'Erorr: Missing',
);
}
echo "$i. {$data[$id]['id']} - {$data[$id]['name']}<br />\n";
}
After you've gotten your $localityResult, you could put all of the id's in an array, then before you echo $localityDataStuff, check to see
if(in_array($i, $your_locality_id_array)) {
// do your echoing
} else {
// echo your not found message
}
To make $your_locality_id_array:
$locality_id_array = array();
foreach($localityResult as $locality) {
$locality_id_array[] = $locality['id'];
}
well, i wanna pull out some data from a mysql view, but the wuery dos not seem to retrieve anything ( even though the view has data in it).
here is the code i've been "playing" with ( i'm using adodb for php)
$get_teachers=$db->Execute("select * from lecturer ");
//$array=array();
//fill array with teacher for each lesson
for($j=0;$j<$get_teachers->fetchrow();++$j){
/*$row2 = $get_lessons->fetchrow();
$row3=$row2[0];
$teach=array(array());
//array_push($teach, $row3);
$teach[$j]=mysql_fetch_array( $get_teachers, TYPE );
//echo $row3;*/
$row = $get_teachers->fetchrow();
//$name=$row[0]+" "+$row[0]+"/n";
//array_push($teach, $row1);
echo $row[0]; echo " ";echo $row[1]." ";
//$db->debug = true;
}
if i try something like "select name,surname from users", the query partially works . By partially i mean , while there are 2 users in the database, the loop only prints the last user.
the original query i wanted to execute was this
$get_teachers=$db->Execute("select surname,name from users,assigned_to,lessons
where users.UID=assigned_to.UID and lessons.LID=assigned_to.LID and
lessons.term='".$_GET['term']."'");
but because it didnt seem to do anything i tried with a view ( when you execute this in the phpmyadmin it works fine(by replacing the GET part with a number from 1 to 7 )
the tables in case you wonder are: users,assigned_to and lessons. ( assigned_to is a table connecting each user to a lesson he teaches by containing UID=userid and LID=lessonid ). What i wanted to do here is get the name+surname of the users who teach a lesson. Imagine a list tha displays each lesson+who teaches it based on the term that lesson is available.
Looking at http://adodb.sourceforge.net/ I can see an example on the first page on how to use the library:
$rs = $DB->Execute("select * from table where key=123");
while ($array = $rs->FetchRow()) {
print_r($array);
}
So, you should use:
while ($row = $get_teachers->fetchrow()) {
instead of:
for ($j = 0; $j < $get_teachers->fetchrow(); ++$j) {
The idea with FetchRow() is that it returns the next row in the sequence. It does not return the number of the last row, so you shouldn't use it as a condition in a for loop. You should call it every time you need the next row in the sequence, and, when there are no more rows, it will return false.
Also, take a look at the documentation for FetchRow().
for($j=0;$j<$get_teachers->fetchrow();++$j){
... a few lines later ...
$row = $get_teachers->fetchrow();
See how you call fetchrow() twice before actually printing anything? You remove two rows from the result set for every 1 you actually use.
while ($row = $get_teachers->fetchrow()) {
instead and don't call fetchrow() again within the loop.
Because you're fetching twice first in the loop
for($j=0;$j<$get_teachers->fetchrow();++$j){
... some code ...
// And here you fetch again
$row = $get_teachers->fetchrow();
You should use it like this
while ($row = $get_teachers->fetchrow()) {