converting sql query to rails 2.3.5 compatible

below is my sql query

SELECT individuals.* FROM ( select children.*  FROM checkins, children WHERE 
checkins.child_id = children.id AND checkins.event_id = 1234 ) temp, 
individuals WHERE temp.individual_id = individuals.id 
ORDER BY individuals.firstname;

can some convert this to rails 2.3.5 compatible (active record find method)

[edited]

SELECT individuals.* FROM ( SELECT children.*  
FROM checkins INNER JOIN children 
ON checkins.child_id = children.id WHERE checkins.event_id = 1234 ) temp 
INNER JOIN individuals ON temp.individual_i开发者_开发技巧d = individuals.id ORDER BY
individuals.firstname;

Individual.find(:all, :joins => {:children => :checkins}, :conditions => 'checkins.event_id = 1234', :order => 'individuals.firstname')