sql_review.sql

select * from orders
--==========================================
select order_id,order_mode from orders
--==========================================
select order_id,order_mode from orders
where order_total > 7000
--==========================================
select count(order_id) from orders
--==========================================
select count(order_id) from orders
where order_total > 15000
--==========================================
select max(order_total) from orders
--==========================================
select min(order_total) from orders
--==========================================
select order_mode,sum(order_total) from orders
group by order_mode
--==========================================
select order_id from orders
where order_total = 
(select max(order_total) from orders)
--==========================================
select order_mode  from 
(select order_mode,sum(order_total) as t from orders group by order_mode)
where t = (select max( sum(order_total) )  from orders group by order_mode)
--==========================================
select order_mode  from 
(select order_mode,sum(order_total) as t from orders group by order_mode)
where t = (select min( sum(order_total) )  from orders group by order_mode)
--==========================================
select * 
from customers
--==========================================
select CUST_LAST_NAME, CUST_FIRST_NAME 
from customers
--==========================================
select CUSTOMER_ID , count(ORDER_ID) as o from orders group by CUSTOMER_ID
--==========================================
select max(count(ORDER_ID)) from orders group by CUSTOMER_ID
--==========================================
select CUSTOMER_ID
from (select CUSTOMER_ID , count(ORDER_ID) as o from orders group by CUSTOMER_ID)
where o = (select max(count(ORDER_ID)) from orders group by CUSTOMER_ID)
--==========================================
select CUST_LAST_NAME, CUST_FIRST_NAME 
from customers
where customer_id in (
select CUSTOMER_ID
from (select CUSTOMER_ID , count(ORDER_ID) as o from orders group by CUSTOMER_ID)
where o = (select max(count(ORDER_ID)) from orders group by CUSTOMER_ID)
)
--==========================================