I added a column to the Investments table, firm_tax, that will display the current firm tax when the investment is done. Here is a quick SQL script I wrote up to add the firm_tax column:
ALTER TABLE Investments ADD firm_tax INT(11) NULL AFTER profit;
ALTER TABLE Investments ALTER firm_tax SET DEFAULT NULL;
I added a column to the Investments table, firm_tax, that will display the current firm tax when the investment is done. Here is a quick SQL script I wrote up to add the firm_tax column: