Script to create a sql admin login user in T-SQL

CreateAdminLoginUser.sql

CREATE LOGIN NewAdminName WITH PASSWORD = 'ABCD'
GO
--Here is how you create a User with db_owner privileges using the Login you just declared:
Use YourDatabase;
GO

IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = N'NewAdminName')
BEGIN
    CREATE USER [NewAdminName] FOR LOGIN [NewAdminName]
    EXEC sp_addrolemember N'db_owner', N'NewAdminName'
END;
GO