Question

I am doing a simple call here and I’m unsure why my results are so erratic.

Foo.maximum('bar')

bar looks like this

|bar |
|-----
|16  |
|5   |
|2   |
|10  |
|7   |
|8   |
|10  |
|9   |

I would expect the call to respond that the maximum value is 16. The only thing noteworthy in respect to these values is that they are, because I have no way of knowing if they are going to come in as an int or a float, actually strings. Could it be getting the max of the character value rather than the numbers themselves?

Answer 1

If you can’t alter the database and need to deal with strings, you could do something in ruby instead. However, it may be expensive if your Foo table has a ton of stuff in it:

Foo.select("bar").collect{|foo| foo.bar.to_f}.max

Or if you wanted to avoid instantiating a bunch of ActiveRecord objects, which the above code would do even with just selecting a single field:

ActiveRecord::Base.connection.query("SELECT bar FROM foo").collect{|foo| foo.first.to_f}.max