DELOITTE SQL Interview Question | SQL Intermediate Question 19 

we can also achive this by using following : with cte as ( select *, LEAD(total_sales_revenue,1) over (partition by product_id order by year) as nxt_rev, LEAD(total_sales_revenue,2) over (partition by product_id order by year) as nxtnext_rev from sales) select p.product_id,p.product_name,p.category from cte c join products p on c.product_id=p.product_id where nxtnext_rev>nxt_rev and nxt_rev>total_sales_revenue

my solution on MSSQL DB: with cte as ( Select * ,case when total_sales_revenue< lead(total_sales_revenue,1, total_sales_revenue+1)over(partition by product_id order by year) then 1 else null end as new from sales ), sales_cte as( Select * from sales where product_id not in (select product_id from cte where new is null) ) select products.* from sales_cte inner join products on sales_cte.product_id = products.product_id group by products.product_id, products.product_name, products.category

First view

with cte as (select *,(lead(total_sales_revenue) over (partition by product_id order by year)-total_sales_revenue)as x from sales) select distinct c.product_id,p.product_name from cte c inner join productss p on c.product_id=p.product_id where c.product_id not in (select product_id from cte where x

Thanks for the video. I used the lag function and used distinct instead of max in the output line. Is it valid? Please check. with cte as ( select p.product_id, p.product_name, s.year, total_sales_revenue, LAG(total_sales_revenue,1) over (partition by p.product_id order by year) as prev_year_revenue from products p join sales s on p.product_id = s.product_id --order by p.product_id, s.year ) select distinct product_id, product_name from cte where product_id not in (select product_id from cte where total_sales_revenue < prev_year_revenue)

can we do it without using a CTE? i suspect we can , though unlikely to be optimal, thoughts??

Hi bro, can you please send me the solution for this question create table brands ( Year int, Brand varchar(20), Amount int ) insert into brands values (2018, 'Apple', 45000); insert into brands values (2019, 'Apple', 35000); insert into brands values (2020, 'Apple', 75000); insert into brands values (2018, 'Samsung', 15000); insert into brands values (2019, 'Samsung', 20000); insert into brands values (2020, 'Samsung', 25000); insert into brands values (2018, 'Nokia', 21000); insert into brands values (2019, 'Nokia', 17000); insert into brands values (2020, 'Nokia', 14000); Write a query to fetch the records of brands whose Revenue is increasing every year? Altough the question you have solved is similar. But differrence is it is a single table and don't have id. I tried to solve the approach you have said. But I can't resolve it. Please make a video or help me in the solution..

bro why don't you explain first logic in excel then jump to sql editor to write. can you explain the logic behind total_sales_revenue>nxt>rvn in excel. because there are for product_id 2 every row doesn't satisfy the codition. but how it is working I didn't get it. Please explain in excel first. I have already given feedback related to you previously.

My solution with cte as ( SELECT * ,LEAD(total_sales1_revenue,1) OVER(PARTITION BY product_id ORDER BY year) Year1 ,LEAD(total_sales1_revenue,2) OVER(PARTITION BY product_id ORDER BY year) year2 ,ROW_NUMBER() OVER (PARTITION BY product_id ORDER BY year) as RW FROM sales1 ) ,cte2 as( SELECT *, CASE WHEN (total_sales1_revenue < Year1 ) AND (Year1 < Year2) THEN 1 ELSE 0 END flag FROM cte WHERE RW = 1 ) SELECT P.* FROM products1 P JOIN cte2 C ON P.product_id=C.product_id WHERE C.flag = 1