Without adding tables or queries, click Close in the Show Table dialog box. Right click once, and select SQL View in the pop up menu. Click on the Run icon to test the query. Repeat step 4 to return to SQL View . Selecting data from the database Relational operations projection, selection and join allow you to tell the system exactly what data you want to see.
Projection selects columns, selection selects rows, and join brings together data in related tables.
This example illustrates how arithmetic operations can be carried out in a query.