Latest calculated Primary key item

Question

Hi ,
I have table structure like below and i need to fetch latest calculated row item for each customer. I need OrderId(PKey) from below table.
OrderID    CustomerId      DateCalculated
1                   1                   1/1/2014
2                    1                   2/1/2014
3                     2                 4/1/2014
4                     2                 5/1/2014
5                     3                  5/1/2014.
I need to fetch laste calculated row for each candidate
OrderId             customerId            
2                                 1
4                                 2
5                                 3
i need orderId in the select list.
Please provide the script for the same.
Thanks in Advance

Answer 1

Please post DDL, so that people do not have to guess what the keys, constraints, Declarative Referential Integrity, data types, etc. in your schema are. Learn how to follow ISO-11179 data element naming conventions and formatting rules (you failed). Temporal
data should use ISO-8601 formats (you failed). Code should be in Standard SQL as much as possible and not local dialect. 
This is minimal polite behavior on SQL forums. 
>> I have table structure like below  ..<<
NO! There is no DDL, no structure shown. Now we have to guess and do your job for you. 
>> .. and I need to fetch latest calculated row item for each customer. <<
Google what a SEQUENCE is, if you do not know
CREATE SEQUENCE Order_Seq
 AS INTEGER
 START WITH 1
 INCREMENT BY 1
 MINVALUE 1
 MAXVALUE 999999
 NO CYCLE; 
CREATE TABLE Orders
(order_seq INTEGER DEFAULT NEXT VALUE FOR Order_Seq 
 PRIMARY KEY,
 customer_id INTEGER NOT NULL
   REFERENCES Customers(customer_id),
 order_date DATE DEFAULT CURRENT_TIMESTAMP NOT NULL);
INSERT INTO Orders (customer_id, order_date)
VALUES
(1, '2014-01-01'),
(1, '2014-01-02'),
(2, '2014-01-04'),
(2, '2014-01-05'),
(3, '2014-01-05');
>> I need to fetch last calculated row for each candidate <<
CREATE VIEW Recent_Orders (recent_order_seq, customer_id)
AS
SELECT MAX(order_seq), customer_id 
  FROM Orders
 GROUP BY  customer_id;
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