SQL对大小写不敏感
#检索单个列
SELECT prod_name FROM products;
#检索多个列
SELECT prod_name,prod_id,prod_price FROM products;
#检索多个列
SELECT * FROM products;
#检索不同的值
SELECT DISTINCT vend_id FROM products;
#限制结果,需要好好理解
SELECT prod_name FROM products LIMIT 5;
SELECT prod_name FROM products LIMIT 4 OFFSET 5; —4是检索的行数，5是从那儿开始
SELECT prod_name FROM products LIMIT 5,2; —逗号前，从哪儿开始，逗号后，检索行数