Question

I’m using the following to create a user if it doesn’t already exist in the database:

use DBExample
GO

IF NOT EXISTS (SELECT * from sys.database_role_members WHERE USER_NAME(member_principal_id) = 'user1')
BEGIN
CREATE USER [user1] WITH PASSWORD = 'abc')
END

EXEC sp_addrolemember 'role1', 'user1'
GO

DBExample already has a user1, so when I try to run the script, SQL Server Management Studio complains about an ‘Incorrect syntax near ‘user1’. (in the create user line)

What am I missing to make this work?

Answer 1

I used the answer found here: https://stackoverflow.com/a/6159882 to make use of variables to substitute the user name to get around the ‘There is already login/user named xxx in the database’ error SSMS was complaining about. The code looks like this at the end:

USE DBExample
GO

DECLARE @userName varchar(100)

SET @userName = 'user1'

IF NOT EXISTS (SELECT * from sys.server_principals WHERE name = @userName)
BEGIN
DECLARE @LoginSQL varchar(200);
SET @LoginSQL = 'CREATE LOGIN ' + @userName + ' WITH PASSWORD = abc';
EXEC (@LoginSQL);
END

IF NOT EXISTS (SELECT * from sys.database_principals WHERE name = @userName)
BEGIN
DECLARE @UserSQL varchar(200);
SET @UserSQL = 'CREATE USER ' + @userName + ' FOR LOGIN ' + @userName;
EXEC (@UserSQL);
END

IF NOT EXISTS (SELECT * from sys.database_role_members WHERE USER_NAME(member_principal_id) = @userName)
BEGIN
EXEC sp_addrolemember 'role1', @userName
END

GO