Yes it stops execution so this is generally preferable to HAVING COUNT(*) > 0 which often won't. With EXISTS if you look at the execution ... ... <看更多>

Use sys.database_principals instead of sys.server_principals . So the final query would look like this (accounting for the user filter): ... <看更多>

... <看更多>

EXISTS is a logical operator that checks if a subquery returns any rows. EXISTS works only with SELECT statements inside the subquery. Let's see ... ... <看更多>