Hello! Help with SQL$,$please$!$

Consider a query written to generate a report with the following structure:

$-$ customer's country code $($billing address$)$;

$-$ average duration of interaction with customer measured in days between first and last order;

$-$ number of online orders created by customers of the country;

$-$ difference between number of online orders and respective arithmetic mean among countries;

$-$ difference between number of offline orders and respective arithmetic mean among countries.

What code should be written in place of $"\_\_\_\_"?$

select a$\_$billing.countryregioncode,

extract$($day from avg$($duration$))$ avg$\_$duration,

round$($sum$($

case

when s$.$onlineorderflag $=$ true then

$1$ else null end$),0)$ online$\_$country,

round$($sum$($

case

when s$.$onlineorderflag $=$ false then

$1$ else null end$),0)$ offline$\_$country,

round$($sum$($

case

when s$.$onlineorderflag $=$ true then

$1$ else $0$ end$)$

$-\_\_\_\_($

case

when s$.$onlineorderflag $=$ true then

$1$ else $0$ end$))$ over$(),2)$ online$\_$country$\_$dev,

round$($sum$($

case

when s$.$onlineorderflag $=$ false then

s$.$totaldue else $0$ end$)$

$-\_\_\_\_($

case

when s$.$onlineorderflag $=$ false then

$1$ else $0$ end$))$ over$(),2)$ offline$\_$country$\_$dev

from $($select $*,$ max$($orderdate$)$ over$($partition by customerid $)$

$-$ min$($orderdate$)$ over$($partition by customerid $)$ duration

from salesorderheader$)$ s

join address a$\_$billing

on a$\_$billing.addressid $=$ s$.$billtoaddressid

group by a$\_$billing.countryregioncode;

Database adventurewokslt

CREATE TABLE public.customer $($

customerid int$4$ NOT NULL,

namestyle bool NOT NULL DEFAULT false,

title varchar$(8)$ NULL,

firstname varchar$(50)$ NULL,

middlename varchar$(50)$ NULL,

lastname varchar$(50)$ NULL,

suffix varchar$(10)$ NULL,

companyname varchar$(128)$ NULL,

emailaddress varchar$(50)$ NULL,

rowguid varchar$(36)$ NOT NULL,

modifieddate timestamp$(6)$ NOT NULL DEFAULT CURRENT$\_$TIMESTAMP,

salespersonid int$4$ NULL,

gender varchar$(1)$ NULL,

totalchildren int$4$ NULL,

birthdate date NULL,

datefirstpurchase date NULL,

persontype varchar$(3)$ NULL,

CONSTRAINT customer$\_$pkey PRIMARY KEY $($customerid$)$

$)$;

CREATE TABLE public.product $($

productid serial$4$ NOT NULL,

"name" varchar$(50)$ NOT NULL,

productnumber varchar$(25)$ NOT NULL,

color varchar$(15)$ NULL,

listprice numeric$(29,3)$ NOT NULL,

"size" varchar$(5)$ NULL,

sizeunitmeasurecode bpchar NULL,

weightunitmeasurecode bpchar NULL,

weight numeric$(8,2)$ NULL,

productline bpchar NULL,

"class" bpchar NULL,

"style" bpchar NULL,

productsubcategoryid int$4$ NULL,

productmodelid int$4$ NULL,

sellstartdate timestamp$(6)$ NOT NULL,

sellenddate timestamp$(6)$ NULL,

discontinueddate timestamp$(6)$ NULL,

CONSTRAINT product$\_$pkey PRIMARY KEY $($productid$)$

$)$;

CREATE INDEX idx$\_$product$\_$color ON public.product USING btree $($color$)$;

CREATE TABLE public.salesorderdetail $($

salesorderid int$4$ NOT NULL,

salesorderdetailid int$4$ NOT NULL,

orderqty int$2$ NOT NULL,

productid int$4$ NOT NULL,

unitprice numeric$(19,4)$ NOT NULL,

unitpricediscount numeric$(19,4)$ NOT NULL DEFAULT $0,$

linetotal numeric$(38,6)$ NOT NULL,

rowguid varchar$(36)$ NOT NULL,

modifieddate timestamp$(6)$ NOT NULL DEFAULT CURRENT$\_$TIMESTAMP,

CONSTRAINT salesorderdetail$\_$pk PRIMARY KEY $($salesorderdetailid$)$

$)$;

CREATE INDEX salesorderdetail$\_$productid$\_$idx ON public.salesorderdetail USING btree $($productid$,$ salesorderid$)$;

ALTER TABLE public.salesorderdetail ADD CONSTRAINT salesorderdetail$\_$fk FOREIGN KEY $($productid$)$ REFERENCES public.product$($productid$)$;

ALTER TABLE public.salesorderdetail ADD CONSTRAINT salesorderdetail$\_$order$\_$fk FOREIGN KEY $($salesorderid$)$ REFERENCES public.salesorderheader$($salesorderid$)$;

CREATE TABLE public.salesorderheader $($

salesorderid int$4$ NOT NULL,

revisionnumber int$2$ NOT NULL DEFAULT $0,$

orderdate timestamp$(6)$ NOT NULL DEFAULT CURRENT$\_$TIMESTAMP,

duedate timestamp$(6)$ NOT NULL,

shipdate timestamp$(6)$ NULL,

status int$2$ NOT NULL DEFAULT $1,$

onlineorderflag bool NOT NULL DEFAULT true,

salesordernumber varchar$(25)$ NULL,

purchaseordernumber varchar$(25)$ NULL,

accountnumber varchar$(15)$ NULL,

customerid int$4$ NOT NULL,

shiptoaddressid int$4$ NULL,

billtoaddressid int$4$ NULL,

shipmethod varchar$(50)$ NOT NULL,

creditcardapprovalcode varchar$(15)$ NULL,

subtotal numeric$(19,4)$ NOT NULL DEFAULT $0,$

taxamt numeric$(19,4)$ NOT NULL DEFAULT $0,$

freight numeric$(19,4)$ NOT NULL DEFAULT $0,$

totaldue numeric$(19,4)$ NOT NULL,

"comment" varchar$(4000)$ NULL,

rowguid varchar$(36)$ NOT NULL,

modifieddate timestamp$(6)$ NOT NULL DEFAULT CURRENT$\_$TIMESTAMP,

CONSTRAINT salesorderheader$\_$pkey PRIMARY KEY $($salesorderid$)$

$)$;

ALTER TABLE public.salesorderheader ADD CONSTRAINT salesorderheader$\_$fk FOREIGN KEY $($customerid$)$ REFERENCES public.customer$($customerid$)$;