1)	$sql="update child set name='Aslam' where id=8";
2)	$sql="update child set roll=1 where id=7";

3) 	$sql="update child set name='$name',roll='$roll' where id=$id";

table

id	salary	bonus	extra	sum..?

01	500	200	300
02	100	200	400
03	500	200	300

$sql=select id,(select sum(salary),(bonus),(extra) as tblSum(Earnings))

from table_name");

ASC
..........
$sql  ="select * from table_name order by id ASC limit 1";
$result  =  mysqli_query($conn,$sql);

DESC
..........
$sql  ="select * from table_name order by id DESC limit 1";
$result  =  mysqli_query($conn,$sql);
......
N:B: order by id, date, age no matter...
......
select all without last one
$sql ="SELECT * FROM table ORDER BY id DESC LIMIT 13 OFFSET 1";

Or...
$sql ="select *from table where id!=(select max(id) from table )";

$sql  ="select id,item,code from html UNION all
                 select id,item,code from css UNION all
                 select id,item,code from bootstrap UNION all
                 select id,item,code from js UNION all
                 select id,item,code from php UNION all
                 select id,item,code from laravel UNION all
                 select id,item,code from mysql UNION all
                 select id,item,code from android UNION all
                 select id,item,code from editor UNION all
                 select id,item,code from softwere UNION all
                 select id,item,code from github UNION all
                 select id,item,code from other
               ";
         $result  =  mysqli_query($code,$sql);

Same output 

$type = 'code_type';

         $all_item ="select *from $type where id!=(select max(id) from $type)";
         $all_row_result = mysqli_query($code,$all_item);

         $last_item ="SELECT * FROM $type ORDER BY ID D

Although VARCHAR supports 
the maximum size at 65535 characters
the actual maximum value depends 
on other columns in the table and 
character set: Maximum row size
 is 65535 bytes in MySQL that shared 
among all columns in the table
except TEXT/BLOB columns.

C:\laragon\etc\apps\phpMyAdmin\templates\login\form.twig

Line no : 51
change : value="{{ default_user }}" to value="root"

phpmyadmin
left side click "new"
right side top "variables"
search "sql_mode"
edit  & remove "ONLY_FULL_GROUP_BY," 

then save

$hostName = "localhost";
 $userName = "root";
 $password = "";
 $dbName = "name";
 
 $mysqli = new mysqli($hostName, $userName, $password, $dbName);
// Make sure table_1 and table_2 same column (same database)
$sql = "insert table_1 SELECT * FROM table_2";
    $query = mysqli_query($mysqli, $sql);
    if($query){
        echo "Success";
    }else{
        echo "Fail";
    }
Or...........
$sql = "insert offline_online2(invoice_id, status) SELECT invoice_id, status FROM offline_online where invoice_id = 'INV-0000121'";
    $query = mysqli_query($mysqli, $sql);
    if($query){
        echo "Success";
    }else{
        echo "Fail";
    }

Source: https://www.youtube.com/watch?v=epIyuRZC_q0&ab_channel=CodingShiksha

NB: Same localhost server

    $sql = "INSERT INTO pos_test.offline_online SELECT * FROM pos_restaurant.offline_online WHERE invoice_id = 'INV-0000120'";
    $query = mysqli_query($mysqli, $sql);
    if($query){
        echo "Success";
    }else{
        echo "Fail";
    }

<?php
    // onlne, offline table [id, invoice_id, status]
    $mysqli = new mysqli($hostName, $userName, $password, $dbName);

    $tableName = 'offline';
    
    $sql = "SELECT * FROM $tableName";
    $query = mysqli_query($mysqli, $sql);
    $row = mysqli_fetch_assoc($query);
    
    $columnList = implode(', ', array_keys($row));

    echo "<pre>";
    var_export($columnList);
    echo "</pre>";
    
    // Fatch offline row
    $sql = "SELECT * FROM offline WHERE status = 'pending'";
    $query = mysqli_query($mysqli, $sql);
    
    while($row = mysqli_fetch_assoc($query)){
        $order_id = $row['invoice_id'];

        $sql2 = "SELECT * FROM $tableName where invoice_id = '$order_id'";
        $query2 = mysqli_query($mysqli, $sql2);
    
        $array = [];
        while($row3 = mysqli_fetch_assoc($query2)){
            foreach($row3 as $key => $value){
               $array[$key] = "'" .$value. "'";
            }
            $valueList = implode(', ', $array);
    
            $sql3 = "INSERT INTO online ($columnList) VALUES ($valueList)";
            $query3 = mysqli_query($mysqli, $sql3);      

            echo (($query3) ? 'Success' : 'Fail');
        }    
    }
?>

<?php
    $hostName = "localhost";
    $userName = "root";
    $password = "123456";

    $offline = "offline";
    $mysqli = new mysqli($hostName, $userName, $password, $offline);
    
    $online = "online";
    $mysqli_online = new mysqli($hostName, $userName, $password, $online);

    $tableName = 'sd_order_list';
    
    $sql = "SELECT * FROM $tableName";
    $query = mysqli_query($mysqli, $sql);
    $row = mysqli_fetch_assoc($query);
    
    $columnList = implode(', ', array_keys($row));

    $sql = "SELECT * FROM list ";
    $query = mysqli_query($mysqli, $sql);
    
    while($row = mysqli_fetch_assoc($query)){
        $invoice_id = $row['invoice_id'];
        
        $tables = ['sd_order_more'=> 'order_id', 'sd_payment_rcvd' => 'invoiceID', 'sd_order_list' => 'orderID',];
        foreach($tables as $key => $value){
            $tableName = $key;
            $columnName = $value;

            $sql2 = "SELECT * FROM $tableName where $columnName = '$invoice_id'";
            $query2 = mysqli_query($mysqli, $sql2);        
            
            $array = [];
            while($row3 = mysqli_fetch_assoc($query2)){
                foreach($row3 as $key => $value){
                    if($value == ''){
                        $array[$key] = 'null';
                    }else{
                        $array[$key] = "'" .$value. "'";
                    }
                }

                $valueList = implode(', ', $array);

                $sql3 = "INSERT INTO $tableName VALUES ($valueList)";
                $query3 = mysqli_query($mysqli_online, $sql3);                 

                $status = (($query3) ? 'Success' : 'Fail') . "<br>";
                
                echo "Invoice id: " .$invoice_id. " Target table: " .$tableName. " status: " .$status. "<br>";
            } 
        }
    }    
?>

<!-- 
    sd_order_more x 1
    sd_payment_rcvd x 1
    sd_order_list x more
-->