To create a new field in a SQLtable, when using SQLiteStudio, you enter code in this fashion:
SELECT * FROM PRODUCT;
PRICE * 1.07 AS TAXED_PRICE
So the first line selects data from the table named, 'PRODUCT'. Then we select three three individual fields, entering the command 'SELECT' on one line, and then each field that you want to display on three separate line.
The sixth line is used to calculate the value for a new field. The code is completed with a another reference to the source table followed by a semi-colon. When running the code you need to click on the play button, or press F9 in SQLiteStudio to execute the query