Database

1. Stop the MySQL service of started

sudo /etc/init.d/mysql stop #On Debian based linux systems (Ubuntu, Mint ...)

sudo /etc/init.d/mysqld stop #On Red Hat Enterprise based Linux systems (CentOS, Fedora, Suse ...)

Select:

    $con = \Drupal\Core\Database\Database::getConnection();

    $query = $con->select('table_name', 't')

        ->fields('t', ['field_1', 'field_2']);



Syatax (Usually used)

mysqldump --host=IP-OR-HOST --user=USERNAME --password=PASSWORD database_name > database_name.sql

mysqldump -h IP-OR-HOST -u USERNAME -pPASSWORD database_name > database_name.sql



Example:



  $con = Drupal\Core\Database\Database::getConnection();

  $start_value = 100000;

  $query = "ALTER TABLE {the_table} AUTO_INCREMENT = $start_value";

  $con->query($query);

The like condition syntax is:

$query->condition('field_name', "%" . $query->escapeLike("The string") . "%", 'LIKE');

Example:

Link : https://www.drupal.org/node/159605

Merge SQL data base: Insert field or update if exist