valid_user

Returns 1 if the specified ID is a valid user or alias in at least one database.

Syntax

valid_user(server_user_id [, database_id])

server_user_id – is a server user ID. Server user IDs are stored in the suid column of syslogins.
database_id – is the ID of the database on which you are determining if the user is valid. Database IDs are stored in the dbid column of sysdatabases.

Example 1 – Shows that the user with an suid of 4 is a valid user or alias in at least one database:
```
select valid_user(4)
```
```
---------------
              1
```
Example 2 – Shows that the user with an suid of 4 is a valid user or alias in the database with an ID of 6.
```
select valid_user(4,6) 
```
```
---------------
              1
```

valid_user returns 1 if the specified server_user_id is a valid user or alias in the specified database_id.
If you do not specify a database_id, or if it is 0, valid_user determines if the user is a valid user or alias on at least one database.

ANSI SQL – Compliance level: Transact-SQL extension.

The permission checks for valid_user differ based on your granular permissions settings.

Granular Permissions	Description
Enabled	With granular permissions enabled, you must have `manage any login` or `manage server` permission to execute valid_user on a `server_user_id` other than your own.
Disabled	With granular permissions disabled, you must be a user with sa_role or sso_role to execute valid_user on a `server_user_id` other than your own.