How can I iterate through a MySQL result set?

Question

Here is the code I'm using:

# Run the query against the database defined in .yml file.
# This is a Mysql::result object - http://www.tmtm.org/en/mysql/ruby/
@results = ActiveRecord::Base.connection.execute(@sql_query)

In my View, here's what I do to see the values:

<pre><%= debug @results %></pre>
Outputs: #<Mysql2::Result:0x007f31849a1fc0>

<% @results.each do |val| %>
   <%= val %>
<% end %>
Outputs: ["asdfasdf", 23, "qwefqwef"] ["sdfgdsf", 23, "asdfasdfasdf"]

So imagine I query something like select * from Person, and that returns a result set such as:

ID      Name      Age
1       Sergio    22
2       Lazlow    28
3       Zeus      47

How can I iterate through each value and output it?

The documentation here is not useful because I have tried methods that supposedly exist, but the interpreter gives me an error saying that those methods don't exist. Am I using the wrong documentation?

http://www.tmtm.org/en/mysql/ruby/

Thanks!

Answer 1

If you are using mysql2 gem then you should be getting the mysql2 result object and according to the docs you should be able to do the following

results.each do |row|
  # conveniently, row is a hash
  # the keys are the fields, as you'd expect
  # the values are pre-built ruby primitives mapped from their corresponding field types in MySQL
  # Here's an otter: http://farm1.static.flickr.com/130/398077070_b8795d0ef3_b.jpg
end

Checkout the documentation here

So in you case you can do the following

<% @results.each do |val| %>
   <%= "#{val['id']}, #{val['name']}, #{val['age']}" %>
<% end %>

Edit: you seem to be referring to the wrong doc check the Mysql2 gems doc.