Global Variables in MS SQL Server

Global variables are pre-defined system variables. It starts with @@. It provides information about the present user environment for SQL Server. SQL Server provides multiple global variables, which are very effective to use in Transact-SQL. The following are some frequently used global variables –

• @@SERVERNAME
• @@CONNECTIONS
• @@MAX_CONNECTIONS
• @@CPU_BUSY
• @@ERROR
• @@IDLE
• @@LANGUAGE
• @@TRANCOUNT
• @@VERSION

These are explained as following below.

1. @@SERVERNAME :
   This is used to find the name of the machine/computer on which SQL Server is running.
   Example –

   Select @@servername

   Output –

   SERVERXX\CTRXREST

2. @@CONNECTIONS :
   This is used to find number of logins or attempted logins since SQL Server was last started.
   Example –

   Select @@connections

   Output –

   59846824

3. @@MAX_CONNECTIONS :
   This is used to find the maximum number of simultaneous connections that can be made with SQL Server or instance in this computer environment.
   Example –

   select @@max_connections

   Output –

   32767

4. @@CPU_BUSY :
   This is used to find the amount of time, in microseconds, that the CPU has spent doing SQL Server work since the last time SQL Server was running.
   Example –

   Select @@cpu_busy

   Output –

   887468

5. @@ERROR :
   This is used to check the error status (succeeded or failed) of the most recently executed statement. It contains Zero (0) if the previous transaction succeeded, else, it contains the last error number generated by the system.
   Example –

   Select @@error

   Output –

   0

6. @@IDLE :
   The amount of time, in microseconds, that SQL Server has been idle since it was last started.
   Example –

   Select @@idle

   Output –

   123691249

7. @@LANGUAGE :
   This is used to find the name of the language that is currently used by the SQL Server.
   Example –

   Select @@language

   Output –

   us_english

8. @@TRANCOUNT :
   This is used to count the number of open transactions in the current session.
   Example –

   Select @@trancount

   Output –

   0

9. @@VERSION :
   This is used to find the current version of the SQL Server Software.
   Example –

   Select @@version

   Output –

   Microsoft SQL Server 2014 (SP3-CU-GDR) (KB4535288) - 12.0.6372.1 (X64)
   Dec 12 2019 15:14:11
   Copyright (c) Microsoft Corporation
   Standard Edition (64-bit) on Windows NT 6.3 <X64> (Build 9600: ) (Hypervisor)