Checking if a SQL Server login already exists

Question

I need to check if a specific login already exists on the SQL Server, and if it doesn\'t, then I need to add it.

I have found the following code to actually add the

Answer 1

Here's a way to do this in SQL Server 2005 and later without using the deprecated syslogins view:

IF NOT EXISTS 
    (SELECT name  
     FROM master.sys.server_principals
     WHERE name = 'LoginName')
BEGIN
    CREATE LOGIN [LoginName] WITH PASSWORD = N'password'
END

The server_principals view is used instead of sql_logins because the latter doesn't list Windows logins.

If you need to check for the existence of a user in a particular database before creating them, then you can do this:

USE your_db_name

IF NOT EXISTS
    (SELECT name
     FROM sys.database_principals
     WHERE name = 'Bob')
BEGIN
    CREATE USER [Bob] FOR LOGIN [Bob] 
END

Answer 2

This is for Azure SQL:

IF (EXISTS(SELECT TOP 1 1 FROM sys.sql_logins WHERE [name] = '<login>'))
    DROP LOGIN [<login>];

Source: How to check whether database user already exists in Azure SQL Database

Answer 3

This works on SQL Server 2000.

use master
select count(*) From sysxlogins WHERE NAME = 'myUsername'

on SQL 2005, change the 2nd line to

select count(*) From syslogins WHERE NAME = 'myUsername'

I'm not sure about SQL 2008, but I'm guessing that it will be the same as SQL 2005 and if not, this should give you an idea of where t start looking.

Answer 4

what are you exactly want check for login or user ? a login is created on server level and a user is created at database level so a login is unique in server

also a user is created against a login, a user without login is an orphaned user and is not useful as u cant carry out sql server login without a login

maybe u need this

check for login

select 'X' from master.dbo.syslogins where loginname=<username>

the above query return 'X' if login exists else return null

then create a login

CREATE LOGIN <username> with PASSWORD=<password>

this creates a login in sql server .but it accepts only strong passwords

create a user in each database you want to for login as

CREATE USER <username> for login <username>

assign execute rights to user

 GRANT EXECUTE TO <username>

YOU MUST HAVE SYSADMIN permissions or say 'sa' for short

you can write a sql procedure for that on a database

create proc createuser
(
@username varchar(50),
@password varchar(50)
)
as
begin
if not exists(select 'X' from master.dbo.syslogins where loginname=@username)
begin
 if not exists(select 'X' from sysusers where name=@username)
 begin
exec('CREATE LOGIN '+@username+' WITH PASSWORD='''+@password+'''')
exec('CREATE USER '+@username+' FOR LOGIN '+@username)
exec('GRANT EXECUTE TO '+@username)
end
end
end