InterSystems IRIS provides an implementation of SQL, known as InterSystems SQL, which you can use within various programmatic contexts.
Also, you can execute InterSystems SQL directly within the SQL Shell (in the Terminal) and in the Management Portal. Each of these includes an option to view the query plan, which can help you identify ways to make a query more efficient.
For an introduction, see Using InterSystems SQL.
For reference information, see the InterSystems SQL Reference.
Availability: All namespaces.