Executes a custom SQL query against your database and returns all the
results. The results will be returned as an array with columns requested
encapsulated as attributes of the model you call this method from. If you
call Product.find_by_sql
then the results will be returned in
a Product
object with the attributes you specified in the SQL
query.
If you call a complicated SQL query which spans multiple tables the columns specified by the SELECT will be attributes of the model, whether or not they are columns of the corresponding table.
The sql
parameter is a full SQL query as a string. It will be
called as is, there will be no database agnostic conversions performed.
This should be a last resort because using, for example, MySQL specific
terms will lock you to using that particular database engine or require you
to change your call if you switch engines.
# A simple SQL query spanning multiple tables Post.find_by_sql "SELECT p.title, c.author FROM posts p, comments c WHERE p.id = c.post_id" # => [#<Post:0x36bff9c @attributes={"title"=>"Ruby Meetup", "first_name"=>"Quentin"}>, ...]
You can use the same string replacement techniques as you can with
ActiveRecord::QueryMethods#where
:
Post.find_by_sql ["SELECT title FROM posts WHERE author = ? AND created > ?", author_id, start_date] Post.find_by_sql ["SELECT body FROM comments WHERE author = :user_id OR approved_by = :user_id", { :user_id => user_id }]
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