Using Environment variables in T-SQL - 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 "read the value of a system environment variable in a T-SQL script" you can set SQL Management Studio to use "sqlcmd Mode".
Then you can use like this:
Print '$(TEMP)'
:r $(Temp)\Member.sql
go
I'm not sure how this is done outside of "SQL Management Studio" but it should be hard to find out.

Answer 2

This should give you a list (provided you allow people to execute xp_cmdshell)
exec master..xp_cmdshell 'set'
Note: xp_cmdshell is a security hazard ...
You could also do this with a managed stored proc an extended stored proc or via a com component.

Answer 3

Hey, if you want to get the server name, just call SELECT ##SERVERNAME

Answer 4

xp_cmdshell is generally best avoided for security reasons.
You're better off using a CLR assembly. Here's a good introduction to creating a CLR assembly.
You can use System.Environment.GetEnvironmentVariable() in C# - you'll find more info on how to do that here.

Answer 5

Thanks for the answers.
They helped me get to a working solution, although this is probably not the most advanced method:
declare #val varchar(50)
create table #tbl (h varchar(50))
insert into #tbl exec master..xp_cmdshell 'echo %computername%'
set #val = (select top 1 h from #tbl)
drop table #tbl
Specifically I was trying to get the hostname, the echo %computername% could be replaced with the hostname system command. But this now works for any environment variable.

Answer 6

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.