The code then sums all of those transactions and returns the value to the
outer query.
The WEEKDAY function is used to determine whether a given transaction occurs on a
weekend or a weekday. If the WEEKDAY function returns a 6 or a 7??”that is, Saturday or
Sunday??”it??™s a weekend transaction.
The COALESCE function returns its first non-null argument. It is used to ensure you
return a zero rather than a null if there was no spending.
CHAPTER 7 n TRACKING EXPENDITURES WITH PAYPAL 150
DETERMINING A WEEKEND DATE IN RUBY
If you need to determine whether a given date is a weekend in Ruby, you can use the following code to
do just that:
class Date
def is_weekend?
self.cwday == 6 or self.cwday == 7 # If it's a Saturday or a Sunday,
# it's a weekend.
end
end
This code extends the Date class to have an additional method, is_weekend?, which returns
true if the given date is on a weekend and false otherwise.
Next, you loop through your results and convert them into an array of data suitable
for graphing:
weeks = []
max_gross=0.
Pages:
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220