Domain shows error Call to undefined function mssql_query()

Symptoms

• Domain example.com shows one of the following errors:

  Uncaught Error: Call to undefined function mssql_query()

  OR

  Uncaught Error: Call to undefined function mssql_connect()

• The domain in question is using PHP version 7.0 or higher:

  MYSQL_LIN: # plesk db “select d.name,h.php_handler_id from domains d join hosting h on h.dom_id=d.id” | grep example.com
  +———————————————+———————+
  | name                    | php_handler_id      |
  +———————————————+———————+
  | example.com             | plesk-php70-fastcgi |

Cause

Webspace example.com calls the mssql_query() or mssql_connect() function, which was completely removed in PHP 7.0.0.

Resolution

Install the sqlsrv extension for PHP 7.0 as described in the following article: How to install mssql or sqlsrv extensions for PHP?

Note: This extension was not officially tested with Plesk and it is not officially supported. Perform all operations at your own risk.