how to check if table exist in update procedure

In Drupal 8/9, you can programmatically check if a specific table name exists in the database using the schema()->tableExists() method provided by the database API.

<?php

use Drupal\Core\Database\Database;


function drupalvip_module_update_9202() {
    // check if table exist, if not install schema
    $table['group'] = [
        'description' => 'Stores IP group addresses.',
        'fields' => [
            'id' => [ 'type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE, 'description' => 'unique ID',  ],
            'name' => [ 'type' => 'varchar', 'length' => 20, 'not null' => TRUE, 'description' => 'group name', ],

        ],
        'primary key' => ['id'],     
    ];
        
    $schema = \Drupal::database()->schema();
    if (!$schema->tableExists('drupalvip_group')) {
        $schema->createTable('drupalvip_group', $table['group']);
    }
}

* Create new database table {mytable2}.
*/
function mymodule_update_9000() {
  $schema['mytable2'] = [
     // table definition array goes here
  ];
  \Drupal::database()->schema()->createTable('mytable2', $schema['mytable2']);
}