1.仅选择表内部分字段的内容
    SELECT first_name, last_name, points
    FROM customers
    image.png
    2.对表中points + 10分
    SELECT first_name, last_name, points, points+10
    FROM customers
    image.png
    3.对points + 10分并且乘以100倍, 并对该列名改为其他别名
    SELECT
    last_name,
    first_name,
    points,
    (points + 10) 100 AS ‘discount_factor’
    FROM
    customers
    image.png
    4.选择表中的州名并保证州名唯一
    SELECT *DISTINCT     state
    FROM customers

    5.从商品表内选择出所有的商品的名字，单元价， 新的价格
    SELECT
    name,
    unit_price,
    unit_price * 1.1 AS new_price
    FROM
    products