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My solution in PostgreSQL: WITH CTE AS (SELECT * , dates - (ROW_NUMBER() OVER(PARTITION BY employee, status ORDER BY dates)::INT) AS grp FROM emp_attendance) SELECT employee, MIN(dates) AS from_date , MAX(dates) AS end_date, status FROM CTE GROUP BY employee, grp, status ORDER BY employee, from_date In my ROW_NUMBER function, I have partitioned by employee and status, and ordered by dates. For each employee, the data is grouped by status and ordered by dates. The row number resets to 1 whenever the status changes (from present to absent or vice-versa) within each employee's partition. I then subtracted the row number from the date to create a group identifier (grp) to identify consecutive dates within the same status for each employee.

CTEs and window functions are new to me in learning stage, but I got this very clearly thanks for the in detail explanation

Hi thoufiq! Here is my simple solution using SQL server: with cte1 as(select employee, dates, dateadd(day,-1*(row_number()over(partition by employee,status order by dates)),dates) as date_grp,status from employee) select employee,min(dates) as from_date,max(dates) as to_date, status from cte1 group by employee,date_grp,status order by employee,from_date;

Thanks for the problem and explaination!. This was my solve: with mycte as ( SELECT *, rank() over(partition by employee, status order by dates) as rn, datepart(day, dates) as theday, (datepart(day, dates) -rank() over(partition by employee, status order by dates)) as diff from emp_attendance ) select employee, from_date, to_date, status from ( select employee, diff, status, min(dates) as from_date, max(dates) as to_date from mycte group by employee, diff, status ) as x order by 1,2,3

this is the corrected data set (the data set in description not included A2) drop table if exists emp_attendance; create table emp_attendance ( employee varchar(10), dates date, status varchar(20) ); insert into emp_attendance values('A1', '2024-01-01', 'PRESENT'); insert into emp_attendance values('A1', '2024-01-02', 'PRESENT'); insert into emp_attendance values('A1', '2024-01-03', 'PRESENT'); insert into emp_attendance values('A1', '2024-01-04', 'ABSENT'); insert into emp_attendance values('A1', '2024-01-05', 'PRESENT'); insert into emp_attendance values('A1', '2024-01-06', 'PRESENT'); insert into emp_attendance values('A1', '2024-01-07', 'ABSENT'); insert into emp_attendance values('A1', '2024-01-08', 'ABSENT'); insert into emp_attendance values('A1', '2024-01-09', 'ABSENT'); insert into emp_attendance values('A1', '2024-01-10', 'PRESENT'); insert into emp_attendance values('A2', '2024-01-06', 'PRESENT'); insert into emp_attendance values('A2', '2024-01-07', 'PRESENT'); insert into emp_attendance values('A2', '2024-01-08', 'ABSENT'); insert into emp_attendance values('A2', '2024-01-09', 'PRESENT'); insert into emp_attendance values('A2', '2024-01-10', 'ABSENT'); SELECT * from emp_attendance;

solving challenging queries from top mnc with nice explanation, great thoufiq keep it up.

with first as ( select *,lag(status,1) over(partition by employee order by dates) as prev_status from emp_attendance ), second as ( select b.* from ( select *,case when status = prev_status then 'SAME' else 'CHANGE' end as status_check from first ) b where b.status_check='CHANGE' ), final as ( select employee ,dates as from_date ,lead(dates,1) over(partition by employee order by dates)-1 as to_date,status from second ) select employee,from_date,coalesce(to_date,from_date),status from final order by employee,from_date;

My solution: WITH cte AS ( SELECT *, CASE WHEN status = LAG(status, 1, status) OVER (PARTITION BY employee ORDER BY dates) THEN 0 ELSE 1 END AS flag FROM emp_attendance ), cte2 AS ( SELECT employee, dates, status, SUM(flag) OVER (PARTITION BY employee ORDER BY dates) AS flag_sum FROM cte ) SELECT employee, MIN(dates) AS from_date, MAX(dates) AS to_date, MAX(status) AS status FROM cte2 GROUP BY employee, flag_sum ORDER BY employee, from_date; Sir, Is there will be any difference i use iif inplace of case Statment???

Man you are legend....great explanation 😮

with A as (select *, row_number() over (partition by employee,status order by dates) as rnk from emp_attendance ), B as ( select *, dates - CONCAT(rnk::text, ' day')::interval as diff from A ) select employee, min(dates) as start_date, max(dates) as end_date, max(status) from B group by employee,diff order by 1,2

I have tried to solve this in MYSQL. with cte as ( select *,row_number() over(partition by employee order by dates) as rn, row_number() over(partition by employee,status order by dates) as rn1 from emp_attendance ) select employee,min(dates) as from_date,max(dates) as to_date,status from cte group by employee,rn-rn1,status order by 1,2

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create table emp_attendance(employee varchar(200), Dates date, status varchar(200)); Insert into emp_attendance values ('A1','2024-01-01','PRESENT'), ('A1','2024-01-02','PRESENT'), ('A1','2024-01-03','PRESENT'), ('A1','2024-01-04','ABSENT'), ('A1','2024-01-05','PRESENT'), ('A1','2024-01-06','PRESENT'), ('A1','2024-01-07','ABSENT'), ('A1','2024-01-08','ABSENT'), ('A1','2024-01-09','ABSENT'), ('A1','2024-01-10','PRESENT'), ('A2','2024-01-06','PRESENT'), ('A2','2024-01-07','PRESENT'), ('A2','2024-01-08','ABSENT'), ('A2','2024-01-09','PRESENT'), ('A2','2024-01-10','ABSENT'); select * from emp_attendance;

@TFQ can we use min and max instead of first_value and last_value in the window function?

Solution in SQL Server with CTE as ( select employee, dates, status, ROW_NUMBER() over(partition by employee, status order by dates) as rn from emp_attendance), CTE2 as ( select employee, dates, status, DATEDIFF(day, rn, dates) as rn2 from CTE) select employee, min(dates) as mindate, max(dates) as maxdates, status from CTE2 group by employee, status, rn2 order by employee, mindate

You can achieve the same differentiation between employees based on status by simply using rank() and partitioning it by employee, status (as in the first cte). WITH rank_cte AS ( SELECT *, rank() OVER(partition by employee, status order by dates) as r FROM emp_attendance ORDER BY employee, dates ), consec_cte AS ( SELECT *, r - row_number() OVER() AS consec FROM rank_cte ) SELECT employee, MIN(dates) AS start_date, MAX(dates) AS end_date, status FROM consec_cte GROUP BY employee, status, consec ORDER BY employee, start_date;

Hi comments box here is my solution: with cte as( SELECT *,dense_rank()over( partition by employee order by employee,dates) as rn, dense_rank() over(partition by employee,status order by employee,dates ) as rn2 from emp_attendance), cte1 as( select employee,dates,status,rn-rn2 as fn from cte order by dates) select distinct employee,first_value(dates) over(partition by employee,fn order by dates )as from_date,last_value(dates) over(partition by employee,fn) as to_date,status from cte1 order by employee,from_da

Sir, Your videos are really awesome. can you make videos for python programming

Perfect Explanation, Thanks!

Nicely explained!

nice to see u again, bro the last Line of your given Data is a little 0 too much insert into emp_attendance values('A2', '2024-01-010', 'ABSENT'); the source is alsmost the same with cte as (select *, row_number() over(partition by employee order by employee, dates) as rn from emp_attendance), cte_present as (select *, row_number() over(partition by employee order by employee, dates) AS RN2 , rn - row_number() over(partition by employee order by employee, dates) as flag from cte where status='PRESENT'), cte_absent as (select *, row_number() over(partition by employee order by employee, dates) as rn3 , rn - row_number() over(partition by employee order by employee, dates) as flag from cte where status='ABSENT' ) select employee , first_value(dates) over(partition by employee, flag order by employee, dates) as from_date , last_value(dates) over(partition by employee, flag order by employee, dates range between unbounded preceding and unbounded following) as to_date , status from cte_present union select employee , first_value(dates) over(partition by employee, flag order by employee, dates) as from_date , last_value(dates) over(partition by employee, flag order by employee, dates range between unbounded preceding and unbounded following) as to_date , status from cte_absent order by employee, from_date with specification rn2, rn3 in MS SQL Server

MySql solution: with cte as ( select *, row_number() over (partition by employee, status order by dates ) as rw, dates - row_number() over (partition by employee order by employee) as diff from emp_attendance order by employee, dates ) select employee, min(dates) as from_date, max(dates) as to_date, status from cte group by employee, status, diff

have a question for you @techTFQ , how much time u have taken to come up for this solution ? just curious to know an approximate time

this one is a very tough question, for what level role was this question asked 😰

I struggled with this. The rn - rn where status = X is a cool pattern.

Thank you very much clear explanation for the solution

This is very usefull information Bro!

How difficult sql queries are to write on real job senario? Intermediate or hard ?

Thank you TFQ

Can you please start a Snowflake Bootcamp ? Will be really helpful.

Sir may we solve this problem using lag() window function?

Tqs For giving Valueble Infomation.

my solution with cte as(SELECT * ,rank() over (partition by employee,status order by dates asc) rnk from emp_attendance order by employee,dates), cte2 as ( select *,(extract(day from dates) - rnk) diff from cte) select employee,min(dates) from_date,max(dates) to_date,status from cte2 group by employee,status,diff

can we expect a question like this for an entry level business analyst ?

MYSQL Solution Select employee,Min(Dates) as From_date,Max(Dates) as End_Date,Status from (Select *,subdate(Dates,interval Row_Number() over (Partition by Employee,Status Order by dates) Day) as Seg from Emp_Attendance)N group by employee,Seg order by Employee, Dates;

Hello my solution in Sql Server: WITH FLO AS ( SELECT *, CASE WHEN STATUS LAG(STATUS,1,'OPOUI')OVER(PARTITION BY EMPLOYEE ORDER BY DATES)THEN 1 ELSE 0 END AS FLAG FROM EMP_ATTENDANCE ), FLO1 AS ( SELECT * , SUM(FLAG)OVER(PARTITION BY EMPLOYEE ORDER BY DATES)AS GRP FROM FLO ) SELECT EMPLOYEE, MIN(DATES)AS FROM_DATE, MAX(DATES)AS TO_DATE, STATUS FROM FLO1 GROUP BY EMPLOYEE, STATUS,GRP ORDER BY EMPLOYEE, FROM_DATE Hope it helps.

If you have any time gap Please make a video about Frequently asking interview questions in sql for Capgemini interview...

I really appreciate .

Here's my take on it via MS SQL server for given dataset ================================================= with cte as (select *, day(dates) - row_number() over (partition by status, employee order by dates) grp from emp_attendance) select employee, MIN(dates) as from_date, MAX(dates) to_date, status from cte group by grp, employee, status order by employee, from_date =================================================

Share some tips to get into a product based company

select max(amount) as thirdhighamount from orders where amount

with cte as(SELECT *, lag(status,1,status)over(partition by employee order by dates) as nxt from emp_attendance),v1 as( select *, sum(case when status = nxt then 0 else 1 end)over(partition by employee order by dates) as grp from cte) select employee,min(dates) as from_date, max(dates) as to_date,status from v1 group by employee, grp,status;

Postgres solution with base as ( select *,ROW_NUMBER() over(PARTITION by employee order by dates asc ) as rn from emp_attendance ) SELECT employee,from_date,to_date,status from ( select employee ,status, diff,Min(dates) as from_date,max(dates) as to_date from ( select *,count(status) over(partition by employee , status order by employee asc, dates asc rows BETWEEN unbounded PRECEDING and CURRENT ROW) as cumulative_count, abs(rn-count(status) over(partition by employee , status order by employee asc, dates asc rows BETWEEN unbounded PRECEDING and CURRENT ROW)) as diff from base ) group by 1,2,3 ) order by 1,2,3

Where we can find the dataset?

Sir Website link not working?

Cte will work in Oracle db ??? Pls confirm???

Isn't this approach more straight forward? WITH grouped_attendance AS ( SELECT employee, dates, status, DATE_SUB(dates, INTERVAL ROW_NUMBER() OVER (PARTITION BY employee, status ORDER BY dates) DAY) AS group_date FROM emp_attendance ) SELECT employee, MIN(dates) AS from_date, MAX(dates) AS to_date, status FROM grouped_attendance GROUP BY employee, status, group_date ORDER BY employee, from_date; I guess you are always overcomplicating things don't know why!

Sir plz do one vd for jr data analyst interview questions and ans like pdf

As always 👍

with cte as( SELECT *, ROW_NUMBER()OVER(PARTITION BY employee, status ORDER BY dates, status) - ROW_NUMBER()OVER(PARTITION BY employee ORDER BY dates, status) as rnk1 FROM attendance ORDER BY 1,2 ) SELECT employee, min(dates) as from_date, max(dates) as to_date, status FROM cte GROUP BY employee,status ,rnk1 ORDER BY 1, 2

Hi Taufiq ,Please confirm my solution is how optimal? with cte as( SELECT *,lead(status,1,null) over(partition by employee order by dates) as next_day,min(dates) over(partition by employee) as start_day FROM emp_attendance) select employee,date_add(LAG(DATES,1,DATE_SUB(START_DAY,1)) OVER(PARTITION BY EMPLOYEE order by dates),1) AS FROM_DATE, dates as TO_DATE,status from cte where status!=next_day or next_day is null;

WITH cte AS( SELECT EMPLOYEE ,DATES ,STATUS ,rownum - SUM(CASE WHEN STATUS = 'PRESENT' THEN 1 ELSE 1 END) OVER(PARTITION BY EMPLOYEE, STATUS ORDER BY DATES) AS test from emp_attendance --where EMPLOYEE = 'A1' ORDER BY EMPLOYEE, DATES ),SUMMARY AS( SELECT EMPLOYEE ,status ,test ,MIN(DATES) AS FROM_DATE ,MAX(DATES) AS TO_DATE FROM cte GROUP BY EMPLOYEE ,status,test ORDER BY FROM_DATE ) SELECT EMPLOYEE ,FROM_DATE ,TO_DATE ,status FROM summary ORDER BY EMPLOYEE ,FROM_DATE;

Someone can pls solve this infosys interview question, Text1 3 Text2 5 Text3 4 Output should be Text1 Text1 Text1 Text2 Text2 Text2 Text2 Text2 Text3 Text3 Text3 Text3 Query should be single line query.

Sir but there should be a query related to MSSQL,because there are people who are using MSSQL only.Need a Practice session on MSSQL

with cte as (select *, Date - INTERVAL '1' DAY * (row_number() over(partition by Employee, Status order by Date asc)) as rnk from EMP_ATD) select Employee, min(Date), max(Date), Status from cte group by Employee, rnk, Status order by Employee, min(date);

🙏

Harris Steven Jones Kimberly Hall Mark

My solution in ms SQL server: SELECT employee,from_date,to_date,Status FROM(SELECT grp,employee,MIN(dates) AS from_date,MAX(dates) AS to_date,min(status) AS Status FROM( SELECT ROW_NUMBER() OVER(PARTITION BY employee ORDER BY dates) -ROW_NUMBER() OVER(PARTITION BY employee,status ORDER BY dates) AS grp,* FROM emp_attendance)a GROUP BY grp,employee)b ORDER BY employee,from_date;

MS SQL approach with a as ( SELECT *, ROW_NUMBER() over(partition by employee order by dates) rn from emp_attendance) ,b as ( select *,rn - ROW_NUMBER() over(partition by employee order by dates) rn2 from a where status like 'PRESENT') ,c as ( select *,rn - ROW_NUMBER() over(partition by employee order by dates) rn2 from a where status not like 'PRESENT') select employee, status, min(dates) from_date, max(dates) to_date from b group by rn2, employee, status union select employee, status, min(dates) from_date, max(dates) to_date from c group by rn2, employee, status order by 1, 3

Harris Maria Clark Jason Moore Ronald

with cte as( select employee,dates,status,DAY(dates)-ROW_NUMBER()OVER(PARTITION BY employee order by dates)rn1 from emp_attendance where status = 'PRESENT'), cte2 as( select employee,dates,status,DAY(dates)- ROW_NUMBER()over(partition by employee order by dates)rn2 from emp_attendance where status = 'ABSENT') select employee,MIN(dates)as FROM_DATE,MAX(dates)TO_DATE,MAX(status)as status from cte group by employee, rn1 UNION ALL select employee,MIN(dates),MAX(dates),MAX(status) from cte2 group by employee,rn2 ORDER BY employee,FROM_DATE,TO_DATE

Martin Matthew Brown Mark Hernandez Karen

Solution Given by claude 3.5 Sonnet: WITH grouped_attendance AS ( SELECT *, DATE_SUB(date, INTERVAL ROW_NUMBER() OVER (PARTITION BY employee, status ORDER BY date) DAY) AS group_date FROM employee_attendance ) SELECT employee, MIN(date) AS FROM_DATE, MAX(date) AS TO_DATE, status FROM grouped_attendance GROUP BY employee, status, group_date ORDER BY employee, FROM_DATE;

My solution in postgresql WITH EMP_ID AS ( SELECT ROW_NUMBER() OVER (PARTITION BY EMPLOYEE ORDER BY EMPLOYEE,DATES) AS EMP_ID,* FROM PRACTISE."emp_attendance"), FLAG AS ( SELECT *, ROW_NUMBER() OVER (PARTITION BY EMPLOYEE,STATUS ORDER BY EMPLOYEE,DATES) AS RN, EMP_ID - ROW_NUMBER() OVER (PARTITION BY EMPLOYEE,STATUS ORDER BY EMPLOYEE,DATES) FLAG FROM EMP_ID ORDER BY EMPLOYEE,EMP_ID,STATUS) SELECT EMPLOYEE,MIN(DATES) AS FROM_DATE,MAX(DATES) AS TO_DATE,MIN(STATUS) AS STATUS FROM FLAG GROUP BY EMPLOYEE,FLAG ORDER BY EMPLOYEE,FROM_DATE