SQL (Structured Query Language) is one of the most important skills for us, data people. So in this article + video, get the necessary SQL skills you need for Data Analysis work.
Step 0: Install MySQL software
I am using the FREE MySQL Community Edition software to learn & practice SQL at home. You can get it from here.
If you have any other database software available (such as SQL Server or Oracle), you can use them to follow this tutorial.
Step 1: Import Awesome Chocolates Dataset
You need some data to practice SQL. So I prepared a sample dataset for a fictional (but yummy) company called Awesome Chocolates.
Download the .SQL file from here.
After you have the file,
- Open MySQL Workbench, login if necessary
- Click on the “server administration” tab (see illustration, click to expand)
- Click on “Data Import/Restore”
- Select the option “Import from self-contained file”
- Specify the path of the downloaded awesome-chocolates-data.sql file
- Start import
At the end of these steps, your MySQL should have the awesome chocolates database. Congratulations 🎉🥳
You can see this from “Schemas” tab on the workbench
Using SQL Server?
You can also use SQL Server to practice SQL. If you are using SQL Server Management Console, then follow below steps to import the data.
- Download this SQL Server Backup file
- Unzip the file
- Open SSMS & right click on the databases and chose “Restore Database” option. Follow the steps on that screen using below screenshots.
Step 2: Learn SQL for Data Analysis with this video
Everything is ready. Time to learn SQL.
I made an hour long tutorial to explain all the necessary SQL concepts for you. In this video, you will learn:
- How to use SELECT statement to answer business questions
- Working with WHERE clause
- Using AND, OR, NOT and combining them to create complex queries.
- Sorting query results using ORDER BY
- Combining data from two or more tables using JOINS
- Creating reports with GROUP BY
- More than 50 example queries, tips and ideas
Please watch the video below or on my YouTube Channel.
The Queries
Here are some of the example queries covered in the video lesson. Feel free to copy paste them in to SQL console to see how they work.
-- Select everything from sales table
select * from sales;
-- Show just a few columns from sales table
select SaleDate, Amount, Customers from sales;
select Amount, Customers, GeoID from sales;
-- Adding a calculated column with SQL
Select SaleDate, Amount, Boxes, Amount / boxes from sales;
-- Naming a field with AS in SQL
Select SaleDate, Amount, Boxes, Amount / boxes as 'Amount per box' from sales;
-- Using WHERE Clause in SQL
select * from sales
where amount > 10000;
-- Showing sales data where amount is greater than 10,000 by descending order
select * from sales
where amount > 10000
order by amount desc;
-- Showing sales data where geography is g1 by product ID &
-- descending order of amounts
select * from sales
where geoid='g1'
order by PID, Amount desc;
-- Working with dates in SQL
Select * from sales
where amount > 10000 and SaleDate >= '2022-01-01';
-- Using year() function to select all data in a specific year
select SaleDate, Amount from sales
where amount > 10000 and year(SaleDate) = 2022
order by amount desc;
-- BETWEEN condition in SQL with < & > operators
select * from sales
where boxes >0 and boxes <=50;
-- Using the between operator in SQL
select * from sales
where boxes between 0 and 50;
-- Using weekday() function in SQL
select SaleDate, Amount, Boxes, weekday(SaleDate) as 'Day of week'
from sales
where weekday(SaleDate) = 4;
-- Working with People table
select * from people;
-- OR operator in SQL
select * from people
where team = 'Delish' or team = 'Jucies';
-- IN operator in SQL
select * from people
where team in ('Delish','Jucies');
-- LIKE operator in SQL
select * from people
where salesperson like 'B%';
select * from people
where salesperson like '%B%';
select * from sales;
-- Using CASE to create branching logic in SQL
select SaleDate, Amount,
case when amount < 1000 then 'Under 1k'
when amount < 5000 then 'Under 5k'
when amount < 10000 then 'Under 10k'
else '10k or more'
end as 'Amount category'
from sales;
-- GROUP BY in SQL
select team, count(*) from people
group by team
SQL Practice Problems
Once you understand the concepts I’ve demoed in the video, try to solve below homework problems.
If you want to cheat, use the solutions tab to see the answers.
INTERMEDIATE PROBLEMS
👉 You need to combine various concepts covered in the video to solve these
1. Print details of shipments (sales) where amounts are > 2,000 and boxes are <100?
2. How many shipments (sales) each of the sales persons had in the month of January 2022?
3. Which product sells more boxes? Milk Bars or Eclairs?
4. Which product sold more boxes in the first 7 days of February 2022? Milk Bars or Eclairs?
5. Which shipments had under 100 customers & under 100 boxes? Did any of them occur on Wednesday?
HARD PROBLEMS
👉 These require concepts not covered in the video
1. What are the names of salespersons who had at least one shipment (sale) in the first 7 days of January 2022?
2. Which salespersons did not make any shipments in the first 7 days of January 2022?
3. How many times we shipped more than 1,000 boxes in each month?
4. Did we ship at least one box of ‘After Nines’ to ‘New Zealand’ on all the months?
5. India or Australia? Who buys more chocolate boxes on a monthly basis?
INTERMEDIATE PROBLEMS:
— 1. Print details of shipments (sales) where amounts are > 2,000 and boxes are <100?
select * from sales where amount > 2000 and boxes < 100;
— 2. How many shipments (sales) each of the sales persons had in the month of January 2022?
select p.Salesperson, count(*) as ‘Shipment Count’
from sales s
join people p on s.spid = p.spid
where SaleDate between ‘2022-1-1’ and ‘2022-1-31’
group by p.Salesperson;
— 3. Which product sells more boxes? Milk Bars or Eclairs?
select pr.product, sum(boxes) as ‘Total Boxes’
from sales s
join products pr on s.pid = pr.pid
where pr.Product in (‘Milk Bars’, ‘Eclairs’)
group by pr.product;
— 4. Which product sold more boxes in the first 7 days of February 2022? Milk Bars or Eclairs?
select pr.product, sum(boxes) as ‘Total Boxes’
from sales s
join products pr on s.pid = pr.pid
where pr.Product in (‘Milk Bars’, ‘Eclairs’)
and s.saledate between ‘2022-2-1’ and ‘2022-2-7’
group by pr.product;
— 5. Which shipments had under 100 customers & under 100 boxes? Did any of them occur on Wednesday?
select * from sales
where customers < 100 and boxes < 100;
select *,
case when weekday(saledate)=2 then ‘Wednesday Shipment’
else ”
end as ‘W Shipment’
from sales
where customers < 100 and boxes < 100;
HARD PROBLEMS:
— What are the names of salespersons who had at least one shipment (sale) in the first 7 days of January 2022?
select distinct p.Salesperson
from sales s
join people p on p.spid = s.SPID
where s.SaleDate between ‘2022-01-01’ and ‘2022-01-07’;
— Which salespersons did not make any shipments in the first 7 days of January 2022?
select p.salesperson
from people p
where p.spid not in
(select distinct s.spid from sales s where s.SaleDate between ‘2022-01-01’ and ‘2022-01-07’);
— How many times we shipped more than 1,000 boxes in each month?
select year(saledate) ‘Year’, month(saledate) ‘Month’, count(*) ‘Times we shipped 1k boxes’
from sales
where boxes>1000
group by year(saledate), month(saledate)
order by year(saledate), month(saledate);
— Did we ship at least one box of ‘After Nines’ to ‘New Zealand’ on all the months?
set @product_name = ‘After Nines’;
set @country_name = ‘New Zealand’;
select year(saledate) ‘Year’, month(saledate) ‘Month’,
if(sum(boxes)>1, ‘Yes’,’No’) ‘Status’
from sales s
join products pr on pr.PID = s.PID
join geo g on g.GeoID=s.GeoID
where pr.Product = @product_name and g.Geo = @country_name
group by year(saledate), month(saledate)
order by year(saledate), month(saledate);
— India or Australia? Who buys more chocolate boxes on a monthly basis?
select year(saledate) ‘Year’, month(saledate) ‘Month’,
sum(CASE WHEN g.geo=’India’ = 1 THEN boxes ELSE 0 END) ‘India Boxes’,
sum(CASE WHEN g.geo=’Australia’ = 1 THEN boxes ELSE 0 END) ‘Australia Boxes’
from sales s
join geo g on g.GeoID=s.GeoID
group by year(saledate), month(saledate)
order by year(saledate), month(saledate);
Resources to Learn More
SQL is a great skill to have if you work with data. Please use below courses, books, articles & websites to learn more.
SQL BOOKs 📚
I recommend getting these SQL books.
SQL COURSEs 💻
I recommend trying out these courses on SkillShare academy.
SQL WEBSITEs 🌐
Do check out these helpful websites to learn and understand various SQL concepts.
If you use my links to purchase the books or courses, I get a small affiliate commission.
There is no extra cost to you, obviously.
SQL Alternatives
If you want an alternative to SQL, consider learning Power Query.
Here is an article and here is a video to help you with that.
All the best 👍
I wish you all the best with your SQL learning. Do let me know in the comments below if you have enjoyed this article and the video.
41 Responses to “Calculate Elapsed Time in Excel [Quick Tips]”
Hi Chandoo,
To calculate time lapses in excel I usually use the DATEDIF function. Even though is undocumented by MS there is a great explanation of its use in Chip Pearson's site :
http://www.cpearson.com/excel/datedif.aspx
Is pretty easy to use and has great flexibility.
See you and keep Excelling!!!
Another great article, I will be linking to it on my blog.
Oliver:
Yes, I think that DATEDIFF do it better.
Great post! This a fantastic tutorial on calculating elapsed time in Excel that could be helpful even to a novice user. Keep up the useful tips!
Also, the Office community on Facebook could really benefit from you knowledge! Check it out at http://www.facebook.com/office
Cheers,
Andy
MSFT Office Outreach Team
hi, Chandoo !!!
for elapsed time , we can use this unique formula either for hours, minutes or seconds : NOW()-A1)
but using respective special number formats
for hours : [h] ==> 46553
for minutes : [m] ==>2793212
for seconds : [s] ==> 167592763
We can also use mean duration for years (orbital period of the Earth around the Sun : i-e tropical year) which is : 365.25 days
and mean duration for month : 365.25/12 days
be Excelent !!!!
@Oliver... Thanks for the pointer to datediff(). I will update the post with information about this as well.
@Glen... thanks for the linklove 🙂
@Andy... Welcome. Thanks for telling us about the office community on FB.
@Modeste ... that is very cool. I will remember these formatting codes for an upcoming article on number formatting codes 🙂
Great tip Chandoo! I use the formula to calculate years elapsed all the time. It can seriously help save a ton of time with calculations. Also, NETWORKDAYS is one that helps and can seriously impress a boss. Keep up the great work here!
No problem! I will definitely be directing people with tough Excel questions to your blog. Keep up the great posts!
Andy
MSFT Office Outreach Team
Hi,
always great posts and a good way to start my day
but regarding the elapsed time calculations: have you never noticed that there is a result difference between using =TODAY()-A1 and using =NETWORKDAYS(A1,TODAY())?
try it for A1= a Monday such as 21sep09 and "today" is e.g. a Thursday; you get 3 or 4 respectively as a result, depending on the formula used; this is because formula =networkdays() always includes both the startdate and the end date and not only the time between these 2.
This is easily corrected/compensated bij always adding a -1 to the =networkdays() formula because the majority of us will count startday as day 0 and then the result will be consistent across the different formulas.
However, you then get into trouble if you calculate the networkdays for a date further in the past and where either the start or end date falls in a weekend.
just thought to point this out as to me these formula's are not interchangeable just like that!
have a great day!
Paul
=DATEDIF([DOJ],TODAY(),"Y") & " Y, " & DATEDIF([DOJ],TODAY(),"YM") & " M, " & DATEDIF([DOJ],TODAY(),"MD") & " D"
This will fix your 30 Days problem
I calculated the time diff between two date+ times by subtracting 2 cells & custom formatted it to "d hh:mm" format.
E.g.
Cell A1 04-Jan-12 6:00 PM
Cell A2 05-Jan-12 4:45 PM
Cell A3 0 22:45 (formula: =A1-A2)
Wat shud i do 2 not display the "zero" values i.e. no. of days in this case is zero hence the cell shud display " 22: 45" and not "0: 22: 45".
@Amol
Try the Custom Format code:
[
<1] hh:mm ; [>=1] d “d” hh:mmHi Chandoo,
If possible to compute the interval of time and date in one column.
In column C I would like to compute the total days and hours . What formula ? Please help
Example.
Column A Column B
2/13/12 3:30 AM 2/14/12 12:00 AM
In referenc to Elapsed time in months
To calculate the elapsed time in months, we can use the formula =(NOW()-A1)/30. This returns the value in 30 day months.
I use to apply formula =ROUND((TODAY()-A1)/30,0). Today, I faced a peculiar situation, A1 has date 01-Mar-2009, and today being 01-Mar-2012, it should be 36 months, but it is showing 37 months!!
Any suggestions to avoid such errors?
Regards,
Prasad DN
All I want to do is add up a series of times and receive a reply that gives me a total. What I used to do was subtrace the end time from the start time and format the result as [hh]:mm but this doesn't seem to work anymore. How has Bill Gates confounded me?
@Pete
I use Excel 2010 and it still works
The times must be entered as times in the format hh:mm:ss or hh:mm without seconds
Adding up times is as simple as =Sum(Range) or =Sum(A2:A10)
then using a Custom Number format as you have mentioned [h]:mm
If this isn't working, 2 ideas
1. Check your times are times and not text
2. Can you share your data or file with us?
My hospital tracks times from patient arrival to various procedures or treatments. When those times cross over midnight, the regular formulas (2nd time minus first time) don’t work because the result is negative and Excel (2007) won’t show a negative number in time format.
I couldn’t find a solution here (chandoo.org) but found one elsewhere that worked and it’s very simple. I would like to share it.
Assuming 1st time in A1 (column for patient arrival time) (11:00 PM), and 2nd time in B1 (column for x-ray given) (12:30 AM)). Should be 1:30 elapsed time.
=B1-A1+(B1<A1) [This comparison is the key to the solution.]
=12:30 AM – 11:00 PM + (12:30 AM < 11:00 PM)
=0.0208 – 0.9583 + (True)
=-0.9375 + (1) [This is the key! If it is false, Excel adds 0. If it’s true, Excel adds 1 and that is what corrects the negative number. Now Excel can interpret the number as a time.]
=0.0625
Converted to hh:mm = 1:30
I wrapped this formula inside an IFERROR one to alert my data entry person if she messed up and applied it to lots of different columns and it has worked wonderfully. No more complaints from the data entry person who just plugs in times from medical charts.
Very interesting solution. Thank you so much for sharing it with all of us.
HI,
I am working on a Xl application..
I want to capture time between two clicks.
Ex, in my application during run somewhere I press OK button and then I click Cancel.. I want to measure time between these two clicks... Is it possible??
Pls help on this...
@shashidhar
The answer is Yes
You will have to add an appropriate VBA event to start and stop a timer.
There are techniques which can time to the millisecond so maybe look those up on the net
WOW!!!!!! I truly love your excel time format program! WHOOOO! I am very interested in how the time formats "update" (manually on a physical keyboard) that "updates" the time into its respective decimal time formats, such as:
YYYY.yyyy, HH.hhh, etc...
How do those formulas or equations work if not in Excel mode? Example: TI calculators, Word, or any other computer language programming? Just wanted to see how it works. E-mail me at Ultra64848689Ti@gmail.com.
Thanks again for an EXCELLENT Excel program into decimal time formats!
Here's an idea: how about creating an APP for iOS and Android? Just wanted to point that out. =-D
Regarding the elapsed time in months:
I made this function to determine the time elapsed since a date using the number of days in each respective month. It's a simple subtraction and I think it works very well:((Year Today-Year A1)*12++(Month Today - Month A1)+(Day Today/Days in Month Today)-Days A1/Days in month A1)
Here's the function:
=((YEAR(TODAY())-YEAR(A1))*12)+(MONTH(TODAY())-MONTH(A1))+(DAY(TODAY())/DAY(DATE(YEAR(TODAY()),MONTH(TODAY())+1,0))-DAY(A1)/DAY(DATE(YEAR(A1),MONTH(A1)+1,0)))
Have a Merry Christmas everyone!!
I need the ability to calculate how much progress we have made between two dates and I want to represent that as a percentage.
I am thinking this would be a combination of today, networkdays & dividing the days elapsed vs the total days. Then it should be as easy as formatting my cell. Any help would be greatly appreciated.
@Christian
Your correct
dates are just numbers and so you can use simple math to derive the percentage
=(Date Now-Start Date)/(End date-Start date)
that will give you a number between 0 and 1
which you can format as a %'age
is there a way out to calculate the productivity for an employee
The day start is at 08:00 and day end is 20:00
The start date / time is recorded and end date / time is recorded
I want to calculate the timelapse taking into consideration the day begin and dayend time.
If the work begins and ends the same day, a simple formula b1-a1 would compute the productivity.
But if the process remains incomplete and is carried over to the next day, then timelines to be computed accordingly
to clarify,
if start time of an activity is 03/15/2015 18:00 hrs and end time is 03/16/2015 11:00 hrs, then the resultant formula should be 5 hrs (ie 18:00 to 20:00 hrs on day1 + 08:00 to 11:00 hrs on day2) ie 2+3
please guide.
Venkatesh, try (b1-a1)-0.5
This will subtract the fixed amount of time between shifts, 12 hours. If the time between shifts varies, then you could reference other cells that contain the variables.
Please help. when I use the networking days formula I get a date (2-may-00) I want actual number of days. I managing projects and I need to know how many days have passed since we received a project to the current date. Please help Thanks
@Aria: Just format the cell as general or number. that will fix the problem.
You rock! I looked at 17 other sites and they all did not work. Yours did. Thanks!
Hi folks ...
calculating age in years , months and days
=text(now()-a1,"yy")&" y " &text(now()-a1,"mm")-1 &" m "&text(now()-a1,"dd") & " d"
Hi, the Elapsed time in days [ =TODAY()-A1 ] works great however, if I do not have a date in A1, it shows 42157. Anyway to get it to display 0 or a Null value?
@Dan
=If(A1="",0,TODAY()-A1)
I get #NAME? and the formula does not work.
Hi Chandoo,
This might be a challenge - I am looking to calculate elapsed time between two columns
Start date Complete date
9/9/2015 7:21 10/2/2015 11:01
I need to take into account the following:
1) The employee works 7:00-3:15 pm each day
2) Std Work hours are 7hrs 45 min each day
3) Need to take into account all holidays in between start and end date
4) Work week is Mon through Friday.
Can you help?
Thanks!
Hi, i have a certain name (wilium) in column A and against this name i have 2 option, 1 Done and 2 Inprogress. i want that i count done again wilium and count inprogress against wilium separately. which formula will work for it??
Hi, i have a certain name (wilium) in column A and against this name i have 2 option, 1 Done and 2 Inprogress in column C. i want that i count done again wilium and count inprogress against wilium separately. which formula will work for it??
Year, month, day results for DoB.
The formulas I have found on the net and the datedif function do not work. This is what I came up with using a Microsoft support paper dated April 1997 with some modifications:
IF(OR(A2>$A$1,ISBLANK(A2)),"",IF(YEAR($A$1)=YEAR(A2),0,IF(MONTH($A$1)>=MONTH(A2),YEAR($A$1)-YEAR(A2),YEAR($A$1)-YEAR(A2)-1))&" years "&MONTH($A$1)-MONTH(A2)+IF(AND(MONTH($A$1)<=MONTH(A2),DAY($A$1)<DAY(A2)),11,IF(AND(MONTH($A$1)=DAY(A2)),12,IF(AND(MONTH($A$1)>MONTH(A2),DAY($A$1)=DAY(A2),ABS(DAY($A$1)-DAY(A2)),DAY(EOMONTH(A2,0))-DAY(A2)+DAY($A$1))&" days")
Check it out...
Hi, Augustin
what about :
calculating age in years , months and days
=YEAR(NOW()-DoB)-1900 & " y " & MONTH(NOW()-DoB)-1 & " m " & DAY(NOW()-DoB) & " d"
Hi Chandoo,
I am looking for help with the elapse time formula. I have a recruitment tracking sheet where we track the number of days the positions are opened, and when they are finally closed.
The opened positions will have a running turnaround time (TAT) formula and I am using this formula:
=NETWORKDAYS (start_date, TODAY (), Holidays2018)
Now, without disrupting the running TAT formula, how do I then get the TAT to stop when we have a final end date? All the information below is row:
- start_date --> Cell A
- TODAY () --> cell B
- end_date --> Cell C
Hope you are able to help. Thanks!
Interesting question. Try this:
Thank you for this helpful article. I was trying for days now to figure it out. Now the only issue I have is that if I do not have a value inputed for =TODAY()-[@[Date Precured]] Date Precured then it shows 44055. How can I get it to leave it blank if there is no data? Thanks again!!!