sqlite : update record using value in another table

As sqlite do not support join table

I have a stock table:

stock(TEXT) Price(TEXT) PriceInUSD(to be update)

e.g. Apple "USD 100" NULL

Orange "HKD 50" NULL

and another exchangeRate table

Currency Rate

e.g. USD 1

HKD 0.13

How can I set PriceInUSD to (substr(Price,5) * exchangeRate.Rate)