mysql - Convert SQL query to Rails2 ActiveRecord query

i have following sql query, i want to convert it to rails 2 ActiveRecord query. SELECT sa.emp_id AS id,sa.emp_name AS Name, sa.emp_supv AS child_id, sa2.emp_name AS child_name FROM employees AS sa LEFT OUTER JOIN employees AS sa2 ON case when ifnull(sa.emp_supv,0)=0 then sa.emp_id else sa.emp_supv end= sa2.emp_id where sa2.emp_name LIKE '%Nancy%'