mysql学习打卡day2

今日成果：

select * from customers where state = 'va';
select * from customers where state = 'VA';
-- sql不区分大小写

select * from customers where state != 'va';
select * from customers where state <> 'va';
-- !=和<>都代表不等于

select * from customers where birth_date >= '1990-01-01';
-- 出生日期大于等于1990年1月1日的顾客?