如何根据某些条件插入或更新？

Question

Can someone please help me with this! I have 2 tables:

1.Existing pricing table with custom date-dependent pricing windows:

  id | prod id |   start    |    stop    |   price  
-----+---------+------------+------------+-----------
   1 |   65210 | 2012-01-01 | 2013-01-01 |  5.00     
   2 |   54841 | 2012-02-05 | 2013-03-01 | 15.00     
   3 |   51518 | 2012-01-01 | 2013-01-01 |  5.00     
   4 |    8402 | 2012-01-01 | 2017-01-01 |  5.00     
   5 |    1520 | 2012-01-01 | 2050-01-01 | 12.00     
   6 |     959 | 2013-10-01 | 2018-01-01 |  5.00  

2."New" pricing data table (used to update table above by each unique prod id ):

 prod id |   start    |    stop    |   price   
  -------+------------+------------+-----------
   65210 | 2013-01-01 | 2025-01-01 |  5.00     
   54841 | 2013-02-05 | 2017-03-01 | 15.00     
     959 | 2013-01-01 | 2017-01-01 |  5.00    

What's the best way to update the stop date in the table 1 with the stop date in table 2 assuming it's still "in window"? If the existing stop date is before the "new" start date, a new pricing record will be created with the new start and stop dates.

Thanks!

Answer 1

...To update the stop date in the table 1 with the stop date in table 2 assuming it's still "in window"...

UPDATE price p JOIN new_price n
    ON p.prod_id = n.prod_id
   AND n.start BETWEEN p.start AND p.stop
   SET p.stop = n.stop

To insert a new record "...if the existing stop date is before the new start date..."

INSERT INTO price (`prod_id`, `start`, `stop`, `price`)
SELECT n.prod_id, n.start, n.stop, n.price
  FROM new_price n JOIN price p
    ON n.prod_id = p.prod_id
   AND n.start > p.stop

Here is SQLFiddle demo