[code]
CREATE TABLE customers
( customer_id number(10) NOT NULL,
  eff_dt varchar2(50) NOT NULL,
  comp_rate number(5) NOT NULL
)
[/CODE]



[code]
INSERT INTO customers values (1000, '2012-01-01', 100)
INSERT INTO customers values (1000, '2013-01-01', 200)
INSERT INTO customers values (1000, '2014-01-01', 300)
INSERT INTO customers values (1000, '2015-01-01', 400)
INSERT INTO customers values (1000, '2015-03-01', 400)
[/code]