mysql add computation results to table column
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I have a mysql tables which has column for salary. I was able to compute for the columns 18% and 9% value by using:

SELECT SALARY, SALARY * .09 as 'PS', SALARY * .12 as 'GS'  FROM database.table;

1. How would I add an additional column on this table based on the result of the sql statement? What I meant is I wanted to add columns 'PS' and 'GS' to my table.

2. If this is possible on the same table, how would I create another table based on the result of the sql statement (new table containing PS and GS) through sql script/statement.
   