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| author | Ryan Bigg <radarlistener@gmail.com> | 2008-12-01 00:24:52 +1030 |
|---|---|---|
| committer | Ryan Bigg <radarlistener@gmail.com> | 2008-12-01 00:24:52 +1030 |
| commit | b3fd941874a66485238dfa624c7ea74dad726dd0 (patch) | |
| tree | 2c82d26cf8648c25e0b4f756ebad2e5dee4aab81 /railties/doc/guides | |
| parent | a92a43c64822cc1922124f0de85e1e67163f8056 (diff) | |
| download | rails-b3fd941874a66485238dfa624c7ea74dad726dd0.tar.gz rails-b3fd941874a66485238dfa624c7ea74dad726dd0.tar.bz2 rails-b3fd941874a66485238dfa624c7ea74dad726dd0.zip | |
Added using an SQL function example to Selecting Certain Fields section as per http://rails.lighthouseapp.com/projects/16213/tickets/36-adding-an-example-for-using-distinct-to-ar-finders
Diffstat (limited to 'railties/doc/guides')
| -rw-r--r-- | railties/doc/guides/source/finders.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/railties/doc/guides/source/finders.txt b/railties/doc/guides/source/finders.txt index 5fc77a5415..4c70c2b20b 100644 --- a/railties/doc/guides/source/finders.txt +++ b/railties/doc/guides/source/finders.txt @@ -246,6 +246,8 @@ If you're getting a set of records and want to force an order, you can use +Clie To select certain fields, you can use the select option like this: +Client.first(:select => "viewable_by, locked")+. This select option does not use an array of fields, but rather requires you to type SQL-like code. The above code will execute +SELECT viewable_by, locked FROM clients LIMIT 0,1+ on your database. +You can also call SQL functions within the select option. For example, if you would like to only grab a single record per unique value in a certain field by using the +DISTINCT+ function you can do it like this: +Client.all(:select => "DISTINCT(name)")+. + == Limit & Offset If you want to limit the amount of records to a certain subset of all the records retrieved you usually use limit for this, sometimes coupled with offset. Limit is the maximum number of records that will be retrieved from a query, and offset is the number of records it will start reading from from the first record of the set. Take this code for example: @@ -675,6 +677,7 @@ Thanks to Mike Gunderloy for his tips on creating this guide. http://rails.lighthouseapp.com/projects/16213-rails-guides/tickets/16[Lighthouse ticket] +* December 1 2008: Added using an SQL function example to Selecting Certain Fields section as per http://rails.lighthouseapp.com/projects/16213/tickets/36-adding-an-example-for-using-distinct-to-ar-finders[this ticket] * November 23 2008: Added documentation for +find_by_last+ and +find_by_bang!+ * November 21 2008: Fixed all points specified in http://rails.lighthouseapp.com/projects/16213-rails-guides/tickets/16-activerecord-finders#ticket-16-13[this comment] and http://rails.lighthouseapp.com/projects/16213-rails-guides/tickets/16-activerecord-finders#ticket-16-14[this comment] * November 18 2008: Fixed all points specified in http://rails.lighthouseapp.com/projects/16213-rails-guides/tickets/16-activerecord-finders#ticket-16-11[this comment] |