I am trying to update thable with select using limit
It's update table fine when we enter "limit" only with one parameter in select query like (limit 50)
But when select with "limit" like (limit $sqlFrom, $sqlTo) it updates the table but skip 2nd (51 to 100) records and again start updating from 101.
It skip every 2nd 50 records
Where is the problem???
Here is the code
$sqlFrom = 0;
$sqlTo = 50;
for($try = 0; $try < 6; $try++)
{
$res = mysql_query("select * from table_name where underprocess = 0 limit " . $sqlFrom . "," . $sqlTo);
while($row = mysql_fetch_array($res))
{
$id = $row['id'];
mysql_query("update table_name set underprocess = 1 where id = " . $id) or die('error');
echo $id;
}
print '<hr/>';
if($sqlFrom != 0)
{
$sqlFrom += $sqlTo;
}
else
{
$sqlFrom = $sqlTo;
}
}//for
This is as expected
When you update rows 1-50 based on your first iteration, you set underprocess = 1. These are ignored in the 2nd call because ask for rows underprocess = 0.
So rows 51-100 in the 1st query are now rows 1-50 for your 2nd query if you like.
You don't need to change your LIMIT range because you always want the "first" 50.
NOTE
Your LIMIT isn't guaranteed anyway because you have no ORDER BY.
Related
I would like to add a counter to show sequence of record inserted per query.
if(isset($_POST['keyword'])){
$keyword = $_POST['keyword'];
if($keyword){
foreach($keyword as $row){
$keyword_exe = $con->prepare("
INSERT INTO t_theme(m_id,keyword,sequence_counter)VALUES('$id','$row', '???')
");
$keyword_exe->execute();
}
}
}
I expect the output will be like this:
I didnt test with INSERT but you can use this when you SELECT
ROW_NUMBER() OVER(PARTITION BY m_id ORDER BY id ASC) sequence_counter
For save some database space
More here
$counter = 0;
$pre_row = 0;
foreach($keyword as $row){
if( $pre_row == $id){
//In row m_id value equal to next value increase counter by 1
$counter++;
}else{
//else start to 1
$counter = 1;
$pre_row = $id;
}
$keyword_exe = $con->prepare("
INSERT INTO t_theme(m_id,keyword,sequence_counter)VALUES('$id','$row', '$counter')
");
$keyword_exe->execute();
}
DEMO
I have the issue with LIMIT with foreach using PHP.
Basics: I have 50 different tables and in every table I have 2 rows.
When I try to add LIMIT 1 to $$modules_for_all, then I see 50 rows, but I want to see only 1. If I add LIMIT 2, then I see 100 rows.
How I can connect all these tables as a one LIMIT 1 to get 1 row in foreach?
<?php
for ($i = 1; $i <= 50; $i++) {
// $array_table_name contains names with tables
$table_names = $array_table_name[$i];
$modules_for_all = 'g_module_for_all_'.$i;
$$modules_for_all = $db->QueryFetchArrayAll("SELECT * FROM $table_names WHERE user='1' LIMIT 1");
}
for ($i = 1; $i <= 50; $i++) {
$modules_for_from = ${"g_module_for_all_$i"};
foreach ($modules_for_from as $m_foreach_as) {
echo $m_foreach_as['id'];
}
}
Example tables:
table_1
id date_added
1 2018-12-01 00:00:00
2 2018-12-02 00:00:00
table_2
id date_added
1 2018-12-03 00:00:00
2 2018-12-04 00:00:00
table_3
id date_added
1 2018-12-05 00:00:00
2 2018-12-06 00:00:00
Example foreach:
<?php
$array_table_name_1 = 'table_1';
$array_table_name_2 = 'table_2';
$array_table_name_3 = 'table_3';
$for_table_1 = $db->QueryFetchArrayAll("SELECT * FROM $array_table_name_1 WHERE id='1' LIMIT 1 ORDER BY date_added");
$for_table_2 = $db->QueryFetchArrayAll("SELECT * FROM $array_table_name_2 WHERE id='1' LIMIT 1 ORDER BY date_added");
$for_table_3 = $db->QueryFetchArrayAll("SELECT * FROM $array_table_name_3 WHERE id='1' LIMIT 1 ORDER BY date_added");
foreach ($for_table_1 as $m_foreach_as) {
echo $m_foreach_as['id'];
}
foreach ($for_table_2 as $m_foreach_as) {
echo $m_foreach_as['id'];
}
foreach ($for_table_3 as $m_foreach_as) {
echo $m_foreach_as['id'];
}
// Now result is '111' but I want only '1' (realted to make LIMIT 1 to all foreach)
The only way to connect the tables is by using a UNION. So you will need to build one large UNION query and then perform the select after the loop:
$tables = array();
for ($i = 1; $i <= 50; $i++) {
// $array_table_name contains names with tables
$table_names = $array_table_name[$i];
$tables[] = "(SELECT * FROM $table_names WHERE user='1')";
}
$query = implode(" UNION ", $tables) . " ORDER BY date_added LIMIT 1";
$result = $db->QueryFetchArrayAll($query);
foreach ($result as $row) {
echo $row;
}
You are gonna have to use UNION ALL for summing this rows together before ordering and limiting the results.
But keep in mind that a query like this will only work if all the tables in your array have the same structure. If they do not, then you will have to be specific in the query to make them have the same fields.
$array_table_name = [
'table_1',
'table_2',
'table_3',
];
$search_id = 1;
$selectsArray = [];
foreach ($array_table_name as $table_name) {
$selectsArray[] = "SELECT * FROM $table_name WHERE id='$search_id'\n";
}
As you see, I am using foreach() and not for() so you won't update the for by decreasing/increasing the number of tables in the array. So to finally have:
$selectsUnion = implode("UNION ALL\n", $selectsArray) . "ORDER BY date_added \nLIMIT 1";
You can see the code tested and query mounted here: https://3v4l.org/HXH2K
I solved my problem using this: foreach ($modules_for_from as $m_foreach_as) if ($tmp++ < 1) {
I followed one link here, and modified my code accordingly. What I am trying to do achieve is for example a table name media_ids contains 45 rows(which is dyanamic), I want to divide the no of rows in a group of 10 rows minimum (in my case four groups of 10 rows and 1 group of 5) and execute code of each group per hour.
For example from select record from id 1 to 10 then second hour from 11 to 20 and so on unless fetches the last record and start again from id 1.
I added a tracker, which check whats the current limit and proceed.But its giving me the required result what I am trying to achieve.
<?php
require('inc/dbConnect.php');
$lastPointerq = "select tracker from media_tracker";
$lastPointerResult = mysqli_query($con, $lastPointerq);
$lastPointerRes = mysqli_fetch_row($lastPointerResult);
$lastPointer = $lastPointerRes[0];
$lastPointer10=$lastPointer+10;
$currentMediaQuery = "select * from media_ids where id > ".$lastPointer." limit ".$lastPointer.",".$lastPointer10."";
$mediaQuery = mysqli_query($con, $currentMediaQuery);
if (mysqli_num_rows($mediaQuery) > 0) {
while ($row = mysqli_fetch_assoc($mediaQuery)) {
// do stuff…
echo $id=$row['id']."<br>";
}
}
else
{echo "0";}
if ($lastPointer + 10 > 40) {
$lastPointer = 1;
} else {
$lastPointer += 10;
}
mysqli_query($con, "update media_tracker set tracker = $lastPointer");
?>
I am assuming you are calling this script every hour via ajax/Js...
In your code if you delete some data from another script you may find your first row id i.e 100 !
require('inc/dbConnect.php');
$limit = 10 ;
$lastPointerq = "select tracker from media_tracker";
$lastPointerResult = mysqli_query($con, $lastPointerq);
$lastPointerRes = mysqli_fetch_row($lastPointerResult);
$lastPointer = $lastPointerRes[0];
$lastPointerRes = mysqli_fetch_assoc($lastPointerResult);
$lastPointer = empty($lastPointerRes['tracker']) ? 0 : $lastPointerRes['tracker'] ;
$lastPointer10=$lastPointer* $limit;
$currentMediaQuery = "select * from media_ids limit ".$limit." OFFSET ".$lastPointer10."";
$mediaQuery = mysqli_query($con, $currentMediaQuery);
if (mysqli_num_rows($mediaQuery) > 0) {
while ($row = mysqli_fetch_assoc($mediaQuery)) {
// do stuff…
echo $id=$row['id']."<br>";
}
}
else
{echo "0";}
//do a total row count query here and set as value of $total rather than 40
$total =40 ;
$flag = ceil($total/$limit);
if ($lastPointer == $flag) {
$lastPointer = 0;
} else {
$lastPointer ++;
}
mysqli_query($con, "update media_tracker set tracker = $lastPointer");
I've seen a couple variations on this, but mainly they swap the entire row rather than just one value in that row, and not dynamically.
Here's the issue:
I have three rows each with the following cells (id, title, content, display_order, visible).
id is auto_increment. title and content are manually entered and visible is a toggle. display_order is set when each row is created and automatically set as the highest integer and set at the bottom of the stack.
I set it like this so that if any of these records were to be manually deleted, i can reorder the stack automatically (if there are 4 records, and I delete #2, the new order resets as 1,2,3 and not 1,3,4).
Each row has a set of up and down arrow buttons that call move.php with queries of id(id), display_order(pos) and direction(dir).
In the move.php it uses a conditional to determine whether to move the record UP or DOWN depending on what the direction variable is set at.
What PHP code do I need to write to take these three variables (id, pos, dir) and swap the value in the table cell display_order: Here's a visual representation
Initial:
id title pos
-----------------
1 slide1 1
2 slide2 2
3 slide3 3
After I click the UP button for record ID #3:
id title pos
-----------------
1 slide1 1
2 slide2 3
3 slide3 2
MIND YOU the ID and POS will not always be the same integer
USING davidethell's suggestion I have created this:
Here's what I have created, but all I'm getting is the echo $newPos rather that is going back to the admin.php:
require ("connection.php");
$id = $_GET['id'];
$pos = $_GET['pos'];
$dir = $_GET['dir'];
if ($dir == 'up') {
$newPos = $pos-1;
} else {
$newPos = $pos+1;
}
$fromRow = "SELECT * FROM pages WHERE display_order = ".$pos."";
$toRow = "SELECT * FROM pages WHERE display_order = ".$newPos."";
$reord = mysqli_query($conn, "UPDATE pages SET display_order = " . $toRow['display_order'] . " WHERE id = " . $fromRow['id']."; UPDATE pages SET display_order = " . $fromRow['display_order'] . " WHERE id = " . $toRow['id']);
if ($reord){
header("Location: admin.php");
}else{
echo $newPos;
}
The problem I'm running into is that it only echos the $newPos
UPDATED CODE:
require ("connection.php");
$fromArray = array();
$toArray = array();
$id = $_GET['id'];
$pos = $_GET['pos'];
$dir = $_GET['dir'];
if ($dir == 'up') {
$newPos = $pos-1;
} else {
$newPos = $pos+1;
}
$fromRow = mysql_query("SELECT * FROM pages WHERE display_order = ".$pos."");
$toRow = mysql_query("SELECT * FROM pages WHERE display_order = ".$newPos."");
$reord = mysqli_query($conn, "UPDATE pages SET display_order = " . $toRow['display_order'] . " WHERE id = " . $fromRow['id']);
$reord = mysqli_query($conn, "UPDATE pages SET display_order = " . $fromRow['display_order'] . " WHERE id = " . $toRow['id']);
if ($reord){
header("Location: admin.php");
}else{
echo $newPos;
}
Result: echos the $newPos instead of return to admin.php
You could use this query:
UPDATE
yourtable INNER JOIN (
SELECT
MAX(yourtable.pos) pos_prec,
curr.pos pos_curr
FROM
yourtable INNER JOIN
(SELECT pos FROM yourtable WHERE id=3) curr
ON yourtable.pos<curr.pos
GROUP BY
curr.pos) cp ON yourtable.pos IN (cp.pos_prec, cp.pos_curr)
SET
pos = CASE WHEN pos=cp.pos_curr
THEN pos_prec ELSE pos_curr END
It's a little bit complicated, but it will swap the value of the position where ID=3 with the value of the position of the preceding item, even if there are gaps.
Please see fiddle here.
EDIT
If there are no gaps, you could simply use this to move ID#3 UP:
UPDATE
yourtable INNER JOIN (SELECT pos FROM yourtable WHERE id=3) curr
ON yourtable.pos IN (curr.pos, curr.pos-1)
SET
yourtable.pos = CASE WHEN yourtable.pos=curr.pos
THEN curr.pos-1 ELSE curr.pos END;
and just use +1 instead of -1 to move down (both UP and DOWN can be combined in one single query if needed).
PHP Code
And this is using PHP and mysqli, and assuming that the position is given:
<?php
$mysqli = new mysqli("localhost", "username", "password", "test");
$pos = 3;
$dir = 'down';
if ($dir == 'up') { $newPos = $pos-1; } else { $newPos = $pos+1; }
if ($stmt = $mysqli->prepare("
UPDATE
yourtable
SET
pos = CASE WHEN yourtable.pos=?
THEN ?
ELSE ? END
WHERE
pos IN (?, ?)
AND (SELECT * FROM (
SELECT COUNT(*) FROM yourtable WHERE pos IN (?,?)) s )=2;"))
{
$stmt->bind_param("iiiiiii", $pos, $newPos, $pos, $pos, $newPos, $pos, $newPos);
$stmt->execute();
printf("%d Row affected.\n", $stmt->affected_rows);
$stmt->close();
}
$mysqli->close();
?>
(i also added a check, if trying to move UP the first pos, or DOWN the last one it will do nothing).
Assuming a $row object with each row data, just do:
if ($dir == 'up') {
$fromRow = $row2;
$toRow = $row1;
}
else {
$fromRow = $row1;
$toRow = $row2;
}
$sql = "UPDATE mytable SET pos = " . $toRow['pos'] . " WHERE id = " . $fromRow['id'];
// now execute your SQL however you want in your framework
$sql = "UPDATE mytable SET pos = " . $fromRow['pos'] . " WHERE id = " . $toRow['id'];
// now execute your SQL however you want in your framework
Put that in a function or class of some kind to make it reusable.
EDIT:
Based on your edits it looks like you are not fetching enough information in your queries. They should be:
$fromRow = mysql_query("SELECT * FROM pages WHERE display_order = ".$pos."");
$toRow = mysql_query("SELECT * FROM pages WHERE display_order = ".$newPos."");
You were only selecting the id field, but then you were trying to use the display_order field.
i will not write you the PHP code. But i will give you the SQL:
Let's say $delta is either +1 if the slide's position should be raised 1, or -1 if the slide's position should be lowered by 1.
$id is the id of the slide. Ow, and let's assume the table is called slides_table.
You will need 2 queries:
update slides_table set pos = pos + $delta where id = $id;
update slides_table set pos = pos - $delta where pos = (select pos from slides_table where id=$id) and id != $id
My page displays an image, and I want to display the previous and next image that is relevant to the current one. At the moment I run the same query 3x and modify the "where" statement with =, >, <.
It works but I feel there must be a better way to do this.
The image id's are not 1,2,3,4,5. and could be 1,2,10,20,21 etc. But if it is much more efficient I am willing to change this.
mysql_select_db("database", $conPro);
$currentid = mysql_real_escape_string($_GET['currentid']);
$query ="SELECT * FROM database WHERE id ='".$currentid."' LIMIT 1 ";
$result = mysql_query($query,$conPro) or die(mysql_error());
$affected_rows = mysql_num_rows($result);
if ($affected_rows==1)
{
$row = mysql_fetch_array($result)or die ('error:' . mysql_error());
$current_id = $row['id'];
$current_header = $row['title'];
$current_description =$row['desc'];
$current_image = "http://".$row['img'];
$current_url = "http://".$row['id']."/".$db_title."/";
$current_thumb = "http://".$row['cloud'];
}
mysql_select_db("database", $conPro);
$query ="SELECT * FROM database WHERE id <'".$currentid."' ORDER BY id DESC LIMIT 1 ";
$result = mysql_query($query,$conPro) or die(mysql_error());
$affected_rows = mysql_num_rows($result);
if ($affected_rows==1)
{
$row = mysql_fetch_array($result)or die ('error:' . mysql_error());
$previous_id = $row['id'];
$previous_header = $row['title'];
$previous_description =$row['desc'];
$previous_image = "http://".$row['img'];
$previous_url = "http://".$row['id']."/".$db_title."/";
$previous_thumb = "http://".$row['cloud'];
}else{
$previous_none = "true"; //no rows found
}
mysql_select_db("database", $conPro);
$query ="SELECT * FROM database WHERE id >'".$currentid."' ORDER BY id ASC LIMIT 1 ";
$result = mysql_query($query,$conPro) or die(mysql_error());
$affected_rows = mysql_num_rows($result);
if ($affected_rows==1)
{
$row = mysql_fetch_array($result)or die ('error:' . mysql_error());
$next_id = $row['id'];
$next_header = $row['title'];
$next_description =$row['desc'];
$next_image = "http://".$row['img'];
$next_url = "http://".$row['id']."/".$db_title."/";
$next_thumb = "http://".$row['cloud'];
}else{
$next_none = "true"; //no rows found
}
mysql_close($conPro);
Thank you for your time
You don't have to do select_db each time. Once you 'select' a db, it stays selected until you select something else.
You can't really get away from doing two separate queries to get the next/previous images, but you can fake it by using a union query:
(SELECT 'next' AS position, ...
FROM yourtable
WHERE (id > $currentid)
ORDER BY id ASC
LIMIT 1)
UNION
(SELECT 'prev' AS position, ...
FROM yourtable
WHERE (id < $currentid)
ORDER BY id DESC
LIMIT 1)
This would return two rows, containing a pseudofield named 'position' which will allow you to easily identify which row is the 'next' record, and which is the 'previous' one. Note that the brackets are required so that the 'order by' clauses apply to the individual queries. Without, mysql will take the order by clause from the last query in the union sequence and apply it to the full union results.
You can get the "previous" one first WHERE id <'".$currentid."' ORDER BY id DESC, and then query for two "above" it: SELECT * FROM database WHERE id >= '".$currentid."' ORDER BY id ASC then it takes only two queries instead of three.