If you don’t need the result from the joined table, a semijoin is often the fastest way. In the given example, if there was more data in the tables, it’s likely

If you don’t need the result from the joined table, a semijoin is often the fastest way. In the given example, if there was more data in the tables, it’s likely the planner would choose that. Not as familiar with MSSQL as MySQL and Postgres so I’m not positive. Also, the good news is the planners are increasingly better at converting your desired end state into queries utilizing features like this, without you explicitly telling them to.