similar to: Using find_by_sql to get the sum of a column

Hi, Is there an easy way of querying an active record for a maximum column value? I need to do queries like: SELECT MAX(salary) FROM employees TIA, Jeroen

How does one do a SELECT MAX query in rails? I''ve searched and searched and tried lots of things with no luck. I want to implement "SELECT MAX(column_name) from table_name and have it return the maximum value from column_name. I just need to get that one value, not the whole object... Thanks for any ideas... Shelby _______________________________________________ Rails mailing

I''m getting the following error unexpectedly for my rails app. I just exported the databae from dreamhost and imported it on textdrive for my rails app. Mysql::Error: MySQL client ran out of memory: SELECT COUNT(*) FROM comments WHERE (comments.listing_id = 2666) /usr/local/lib/ruby/gems/1.8/gems/activerecord-1.13.2/lib/active_record/connection_adapters/abstract_adapter.rb:88:in

When using PHP, I was able to enter a query against my list of invoices such as : Select SUM(amount) from invoices where project="123" This would give me the total amount of all invoices for project 123. In rails, how would I do this? I tried using "find_by_sql," but couldn''t figure out how to extract the results out of this. Thanks!

I want to return an int from a find_by_sql call. But when I use that result to compare to another count the error tells me I have an array. MODEL: # Returns the number of comments in a specified post def self.find_count(post_id) find_by_sql(["SELECT COUNT(*) FROM commments WHERE post_id = ?", post_id]) end CONTROLLER: def test @post =

I have a little web app where we need to paginate collections of items. I''m trying to sort the collection and then pass it, sorted, to a Paginator, and still be able to paginate through the collection, across several pages, with the new sort order. The only thing I''m doing differently from the regular scaffolding approach is this: @order_pages = Paginator.new(self,

Hi, I''d like to do a "find_by_sql" without a model (e.g. <model name>.find_by_sql("...")) as the results I get back are a once off special, and I''m happy to handle them as an array. How do I do this? "ActiveRecord::Base.find_by_sql(...)" does not seem to work? Background - At the moment I''m doing within a model <model_name>,

Hi All, I am inserting data from one table to another by using following method @data=RoyaltyReportFiles.find_by_sql("insert into royalty_reports (artist_name, album_name) select artist_name, album_name from temp_royalty_reports where id=328417") it saves the data into royalty_reports table but it gives following error and application crashes. i am using rails 1.2.5 You have a nil

Hi all, Is there a way to create pagination with a complex SQL, more complex than the :conditions option will support? I have two databases, houses and images. Houses has_many images, and each Image belongs_to house. I''m creating a search engine for the house records and I''d like to be able to filter out all the houses without any associated images. So far I''m

I have some legacy tables that I used set_table_name on, I''m attempting to write a method that will get key value from a sequence table and then update it and return a value. I''m hoping to put this in the base ActiveRecord method so I would like to reference the table name with self.table_name or something... class Contacts < ActiveRecord::Base set_table_name

I am building an invoicing system but cannot use the auto_increment field to determine the invoice number (because they are running 3 different companies off the one system. I need to find the last invoice number from any given company and then add 1 to it to get the next invoice number. BUT, there is a unique case on the very first invoice produced because there is no earlier invoice

How do you run an ad-hoc query that does not belong in any model? I thought it was something like ActiveRecord::connection.find("my query..."), but I can''t seem to find the documentation on it. I know I''ve seen it somewhere before, though. thanks, Jeff -- Posted via http://www.ruby-forum.com/.

Hello, I''m interested in learning what folks in the Rails community do when they need to generate permanent unique numbers for tracking objects such as packing slips, inventory items, customers, employees, etc. It''s tempting to use the autogenerated id, but they''re not pretty enough for human consumption and it can be problematic having assigned ids if tables ever need

Hi, My results are getting out of order after I do the following command: count = result.inject({}) { |hsh, row| hsh[row[''name'']] = row[''count''].to_i; hsh } Why? Here are more specifics: My complete method is this (based off of acts_as_taggable code - not'' DHHs, but the original one): def self.sql_to_count_plays(lookback) sql =

Hello-- There must be a better way to do this. I have a class method in my model that finds averages and does a few calculations using find_by_sql. The problem I¹m encountering is that all computed columns from MySQL come back as type string. E.g., def self.find_averages(domain_id) if @@domain_average return @@domain_average else @@domain_average =

I have two tables, applicants, and skills where each applicant "has_many" skills, and each skill "belongs_to" an applicant. When I have a reference to an applicant and a (skill) id for one of their skills, I thought to update their skills by using @applicant.skills.find(id_of_skill).description = ''new description'' # even adding

I''m trying to get the following statement to work using variable substitution (it works if hard-code the where (med_type) param in the inner SQL statement): med_type = ''game'' @mediaformats = MediaFormat.find_by_sql("select * from media_formats where media_formats.media_type_id = (select media_type_id from media_types where media_type = ?, :med_type) order by

I tried to use named parameters in my SQL query , using find_by_sql Order.find_by_sql ([select * from orders where amount > ? and quantity > ?", [ @amount, @quantity ] works;.. but Order.find_by_sql ([select * from orders where amount > :amount and quantity > :quantity ", [ :amount => @amt, :quantity => @qty ] is not working a I wrong or should I use a plain select

I have a bunch of queries to compute some counters, like find_by_sql(<<-SQL SELECT p.*, c.nfavourites FROM people p, ( SELECT fp.person_id, COUNT(fp.user_id) as nfavourites FROM favourite_people fp, users u WHERE fp.user_id = u.id AND u.cluster = ''#{in_cluster_of_user.cluster}'' GROUP BY fp.person_id ) as c WHERE

Hi All, Is there a way to do join queries with find() or is it best to use find_by_sql() instead? I''m looking to do something like: SELECT winery_name, wine_name FROM winery, wine WHERE wine.winery_id = winery.winery_id AND winery.winery_name LIKE ''Borg%''; Thanks! : ) Jason