1、2018年4月份的用户数、订单量、销量、GMV （不局限与这些统计量，你也可以自己想一些）

-- -- -- 2018年4月份的用户数量
select
    count(a.user_id) as user_nums
from
    (
        select
            user_id
        from
            app_jypt_m04_ord_det_di
        where
            dt >= '2018-04-01'
            and sale_ord_dt <= '2018-04-30'
            and sale_ord_dt >= '2018-04-01'
        group by
            user_id
    )
    a;
-- 2018年4月份的订单量
select
    count(a.sale_ord_id) as sale_nums
from
    (
        select
            sale_ord_id
        from
            app_jypt_m04_ord_det_di
        where
            dt >= '2018-04-01'
            and sale_ord_dt <= '2018-04-30'
            and sale_ord_dt >= '2018-04-01'
        group by
            sale_ord_id
    )
    a;
-- -- 2018年4月份的销量
select
    sum(COALESCE(sale_qtty, 0)) as xiaoliang
from
    app_jypt_m04_ord_det_di
where
    dt >= '2018-04-01'
    and sale_ord_dt <= '2018-04-30'
    and sale_ord_dt >= '2018-04-01';
-- -- -- 2018年4月份的销售额GMV
-- user_payable_pay_amount 用户应付金额
select
    sum(user_payable_pay_amount) as xiaoshoujine
from
    app_jypt_m04_ord_det_di
where
    dt >= '2018-04-01'
    and sale_ord_dt <= '2018-04-30'
    and sale_ord_dt >= '2018-04-01';

PS:

• 订单数就是卖了几单 ；
• 销量就是卖了多少件，一个订单中可能卖出一件或多件；
• GMV: Gross Merchandise Volume，是成交总额（一定时间段内）的意思。
• 在电商网站定义里面是网站成交金额。这个实际指的是拍下订单金额， 包含付款和未付款的部分。

2、上述这些变化量相对3月份的变化

**
3、计算2018年4月1号的新用户数量（之前半年未购买的用户为新用户）**

-- 计算2018年4月1号的新用户数量（之前半年未购买的用户为新用户）
-- 首先找出4月1号的用户的xxx，然后统计半年内有过购买记录的用户yyy。


-- select distinct user_id as xxx from gdm_m04_ord_det_sum where dt>='2018-04-01' and sale_ord_dt='2018-04-01';
-- select distinct user_id as yyy from gdm_m04_ord_det_sum where dt>='2017-10-01' and sale_ord_dt<='2018-03-31' and sale_ord_dt>='2017-10-01';

-- 用xxx-yyy,然后count()计算数量;



-- 两种方法，一种用not in ，一种用not exists

-- not in 方法
select distinct user_id from gdm_m04_ord_det_sum 
where user_id not in (select distinct user_id from gdm_m04_ord_det_sum where dt>='2017-10-01' and sale_ord_dt<='2018-03-31' and sale_ord_dt>='2017-10-01');



-- not exists 方法
select distinct user_id from gdm_m04_ord_det_sum where dt>='2018-04-01' and sale_ord_dt='2018-04-01' where not exists (select distinct user_id from gdm_m04_ord_det_sum where dt>='2017-10-01' and sale_ord_dt<='2018-03-31' and sale_ord_dt>='2017-10-01' where gdm_m04_ord_det_sum.user_id=gdm_m04_ord_det_sum.user_id);



-- 另一种 left outer join 这样效率更高 语法有问题？？

select distinct user_id from gdm_m04_ord_det_sum where dt>='2018-04-01' and sale_ord_dt='2018-04-01' a left outer join (select distinct user_id from gdm_m04_ord_det_sum where dt>='2017-10-01' and sale_ord_dt<='2018-03-31' and sale_ord_dt>='2017-10-01' b) on a.user_id=b.user_id where b.user_id is null;

正确方法：

select
    count(a.id1) as user_new_nums
from
    (
        select distinct
            user_id as id1
        from
            app_jypt_m04_ord_det_di
        where
            dt >= '2018-04-01'
            and sale_ord_dt = '2018-04-01'
    )
    a
left outer join
    (
        select distinct
            user_id as id2
        from
            app_jypt_m04_ord_det_di
        where
            dt >= '2017-10-01'
            and sale_ord_dt <= '2018-03-31'
            and sale_ord_dt >= '2017-10-01'
    )
    b
on
    a.id1 = b.id2
where
    b.id2 is null;