Using Environment variables in T-SQL

Question

How can I read the value of a system environment variable in a T-SQL script?

This is to run on SQL Server 2005.

Answer 1

To determine a specific environment variable in T-SQL (MS SQL Server) you can do something like:

Grant Security Permissions

use [master]

execute sp_configure 'show advanced options', 1
reconfigure
go

execute sp_configure 'xp_cmdshell', 1
reconfigure
go

grant execute on xp_cmdshell to [DOMAIN\UserName]

grant control server to [DOMAIN\UserName]
go

Source: https://stackoverflow.com/a/13605864/601990

Use Environment Variables

-- name of the variable 
declare @variableName nvarchar(50) = N'ASPNETCORE_ENVIRONMENT'

-- declare variables to store the result 
declare @environment nvarchar(50)
declare @table table (value nvarchar(50))

-- get the environment variables by executing a command on the command shell
declare @command nvarchar(60) = N'echo %' + @variableName + N'%';
insert into @table exec master..xp_cmdshell @command;
set @environment = (select top 1 value from @table);

-- do something with the result 
if @environment = N'Development' OR @environment = N'Staging'
    begin
    select N'test code'
    end
else 
    begin
    select N'prod code'
    end

Also remember to restart the SQL Server Service when changing the Environment Variables.