我需要写一个查询

CREATE TABLE sales (
    OrderID INT,
    OrderDate DATE,
    OrderPrice INT,
    OrderQuantity INT,
    customerName VARCHAR(20)
);

这是我的桌子

+---------+------------+------------+---------------+--------------+
| OrderID | OrderDate  | OrderPrice | OrderQuantity | customerName |
+---------+------------+------------+---------------+--------------+
|       1 | 2005-12-22 |        160 |             2 | Smith        |
|       2 | 2005-08-10 |        190 |             2 | Johason      |
|       3 | 2005-07-13 |        500 |             5 | Baldwin      |
|       4 | 2005-07-15 |        420 |             2 | Smith        |
|       5 | 2005-12-22 |       1000 |             4 | Wood         |
|       6 | 2005-10-02 |        820 |             4 | Smith        |
|       7 | 2005-11-03 |       2000 |             2 | Baldwin      |
+---------+------------+------------+---------------+--------------+

在那里我需要得到所有花费超过1200美元的独特客户的名字