Question

can anyone generate a query for me.
Lets say i have a table sales(saleID, date_of_sales, customerID, itemID, saleprice)

• date_of_sales is the datetime field which stores the time of the sale.

• customerID is self exlpaining tells to whom item was sold.

• itemID is ID of the item sold.

• saleprice is the price that the item was sold.

I want to construct a query which will give out the detail of the last purchase by each customers. this could be done by using date_of_sales.

Example table

saleID | date_of_sales | customerID | itemID | saleprice

101 | 2008-01-01 | C2000 | I200 | 650 |
102 | 2010-01-01 | C2000 | I333 | 200 |
103 | 2007-01-01 | C3333 | I111 | 800 |
104 | 2009-12-12 | C3333 | I222 | 100 |

this is the example data table, there are only two customer for simplicity.

• customer C2000 did his last purchase
  on 2010-01-01

• customer C3333 did his last purchase
  on 2009-12-12

I want to get a result like this

customerID | date_of_sales | itemID | saleprice

C2000 | 2010-01-01 | I333 | 200 |

C3333 | 2009-12-12 | I222 | 100 |

Answer 1

This might be what you are looking for…

SELECT *
    FROM sales
    WHERE sales.date_of_sales = (SELECT MAX(date_of_sales)
                                     FROM sales s2
                                     WHERE s2.customerID = sales.customerID);

There is a slight problem with it; if there were two sales on the same day to the same customer, you’ll get two rows (unless your date-of-sales column includes the time as well). I think the same applies to the answer above, though.