Solving SQL Query | Rows to Column in SQL
ฝัง
- เผยแพร่เมื่อ 11 ก.ค. 2024
- In this video, we will solve an SQL Query where we will need to transform data from rows to column.
We can transform data from rows to column in SQL using PIVOT operator but not all RDBMS supports PIVOT. Microsoft SQL Server and Oracle supports PIVOT operator, whereas in PostgreSQL, we can transform rows to column using CROSSTAB function. Similarly in MySQL database, rows to column transformation can be done using the CASE statement.
Hence in this video, we shall first look at the SQL query problem statement. We understand the input data and also understand the expected output. After this we shall write SQL query to solve this problem using PIVOT in Microsoft SQL Server and in Oracle.
We shall then solve the same problem in PostgreSQL database using CROSSTAB function. Finally we shall also solve this query in MySQL database using the CASE statement.
All the datasets, scripts and SQL queries used in this video can be downloaded from my blog and from my discord channel. Links below:
Blog: techtfq.com/video/solving-sql...
Discord: / discord
If you would like to share any interesting SQL query with me so that I can make a video about it then do share them in the email below:
Email id: techtfq@gmail.com
Timestamp:
00:00 Intro
01:58 Understanding the SQL Query Problem statement
04:20 Solving SQL Query in Microsoft SQL Server using PIVOT
26:59 Solving SQL Query in Oracle using PIVOT
32:46 Solving SQL Query in PostgreSQL using CROSSTAB
55:31 Solving SQL Query in MySQL using CASE statement
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THANK YOU,
Thoufiq
![fellow fellow - Proud [OFFICIAL MV]](http://i.ytimg.com/vi/9uZF7BlUQPE/mqdefault.jpg)
Your content is what I am following from my initial days of learning sql. If possible please make more practise videos on sql with concepts every week/weekend so that our logic buildng can increase week by week. Thanks for the good content.
Bro you are one of the best trainers I could ever come across. To the point and the crystal clear. Thanks one again.
This is the best crosstab explanation I've seen. Thank you!!!
Your videos are quite incredible, thank you Thoufiq for your patience and knowledge.
till i watched this video, i was scared about pivot query, now i can understand it easily. thank yo so much for the video
Everytime you upload a new video, it brings abundance of knowledge in our lives. Thanks for this quality content.
Maza aa jata hai aapka explanation sunke😁
Please consider making videos on topics such as Indexing(in depth) and database designing if possible.
Thank you Rohit..
Very happy to read your positive feedback ❤️
Taufiq sir, absolutely clear the "without ORDER BY clause in postgre SQL Crosstab"...what ever customer is visible as per the sequence , CROSSTAB is grouping those visible data. That's why ORDER BY is mandatory otherwise this weird type data will be show. Thank you sir
Although i am not an English speaker, that does not prevent me from following you. It is very well explained with well chosen examples.
I learned a lot thanks to you. Believe me you are the best. I copied the exact same query using crosstab and when i added the second
argument i got the error : column ("Jan-21") does not exist. I hope you can explain the origin of the problem to me. GREAT THANKS
(i replaced ("Jan-21") with (' 'Jan-21' ') and it worked)
this is a great one. thanks. i always wanted to do pivot queries. never really got around to it. now i got to learn it with my current project. very helpful video. thanks
thanks again. I just completed my report. Just have few little things to add but this video was very handy.
Good video, but for SQL Server i would recommend you look at the GROUPING SETS command.
With that you can rewrite your query to below :
When using "set statistics time on;" you can see it beeing a lot faster.
;with inner_data as
(
select
customer_id as Customer
,format(sales_date, 'MMM-yy') as sales_date
,cast(replace(amount, '$', '') as int) as amount
from sales_data
)
select *
from (
select
isnull(Customer, 'Total') as Customer,
isnull(sales_date, 'Total') as sales_date,
case when sign(sum(amount)) = -1 then concat('(', ABS(sum(amount)), ')$') else concat(sum(amount), '$') end as amount
from (
SELECT a.Customer, b.sales_date, 0 as amount
from
inner_data a inner join
inner_data b
on a.Customer b.Customer and a.sales_date b.sales_date
union all
select
Customer
,sales_date
,amount
from inner_data ) a
group by GROUPING SETS( (Customer, sales_date), (Customer),(sales_date))
) as sales
pivot
(
max(amount)
for sales_date in ([Jan-21], [Feb-21], [Mar-21], [Apr-21]
,[May-21], [Jun-21], [Jul-21], [Aug-21]
,[Sep-21], [Oct-21], [Nov-21], [Dec-21],[Total])
) as pivot_table
Outstanding. worked perfectly (for MySql). Thanks heaps
Glad to hear that
Thank you so much... helping multi tools at same time...
Great content, helped with exactly what I needed for my current task at work. Thanks a lot !
This is the best explanation! Thank you so much ❤
Good video sir it is very help full and iam alway thankful to you sir ,sir kindly provide every week one imortant video
Thank you bro..
And sure will try doing it bro
that was some useful stuff man, thankyou so much.
mark my words "im going to get a data analyst job soon " and you are playing very important role in my journey.
I hope you got the job you wanted, any updates? I just started to understand the fundamentals of data engineering and I would love to hear how your journey is going and what helped you the most
I m so thankful to you brother....i must say video is very informative which is helping me to increase my skills on SQL...!! 👍
thank you Sandeep :)
Just wanted to say Thanks!!! Your sql joins video helped me crack my first tech interview. Kep up the good work brother.....
thank you, Great to hear Abhijeet!
Tofik, you are legend!
your video is very helpful for me. thank you. 👍
Hi Taufiq Just one word you are the best !!!! when it comes to sql
What an outstanding video! Ver well done! Thank you for putting it together. I have a question, though. I'm primarily a MySQL users but also use SQL Server. How could we set this up to be more dynamic? For example, let's say your column table covered 24 months and had 5 customers. Instead of writing out 24 lines of code each time (1 for each column) and then 24 lines multiple times, is there a way to write much fewer lines using variables, loops and a WITH clause? Thanks again - your videos have taught me so, so much!
Garrett Evans Wow thank you Garrett, you've made my day!
Awesome explanation! As always. Great thanks!
Glad you liked it :)
Very helpful and thank you for your time and effort to make this excellent video.
I also searching the same....But finally got from you
Thank you
Awesome. Great video! Much helpful
This video saved me! Thank you sir.
Mannnn you are simply the best ever, thanks so much, it helps a lottttttttttt!!!!
Glad to hear that ☺️
My God...........so many learnings in just one video
thanks bro
Great 👍 content as always 👌 thank you
Glad you liked it buddy
Thanks for the explanation. Ur explanations are crystal clear.
I subscribed to ur channel..☺️
You are a Big treasure, bro. ❤
Good video.
You can wrap base query in (Double Dollar) $$ SUBQUERY $$ for postgres. Then you don't need to escape single quotes and makes it easy to read and write subquery.
This was a great video! I also loved how well you presented it, explaining every little detail. That way it is easy to remember the syntax. Thank you!! This was super helpful. Earlier I used to do sum() or max() to get a pivot output in postgres. crosstab will make my life a lot easier.
One question - Is there a way we can dynamically populate the values for "as" and "values". For instance, instead of months, I have a list of products (which is dynamically populated) and I want to pivot customer against products. Is this possible in postgres?
Thank you 🙏🏼
Instead of values you can provide an sql query as the second argument in crosstab..
But this query should just return 1 column
@@techTFQ Thank you!! I will try this 🙏🏼
Tf...awesome and great work. Although I have been writing SQL for several years, i could learn few new tips and tricks from you. I have a suggestion. Can you come up with a video that shows how to calculate cumulative totals and average totals on a rolling window. for e.g i need to calculate a 9 quarter ( 27months) average balance and cumulative losses. I have seen your window function video but that video lacks a real life problem solving component
honestly thank you for the video , but i learnt sub query in a different way , and you adding alias name in front and few things made me confuse a bit tbh , i understood the concept , thank you
thanks but don't confuse this with subquery. Ive made separate video for subquery.
@@techTFQ but you wont call this a subquery? ohh , i thought the end part as corelated subquery
This is the syntax for pivot operator..
Hi, your videos are very helpful. Could you please upload the data sets you used in this video? I've checked in discord but I did not find any. Appreciate all your efforts 👍
awesome taufiq....you are a star
Great work techTFQ
good work 👍
Your every content are amazing and very well explained.Can you please create playlist around SQL query tuning and performance?
Thank you Amit , glad you like them..
And noted on the suggestion
@@techTFQ thank you
Great one thanks boss
🤩 you deserve millions subscribers bro
Thank you so much :)
While useful this video confirms one of my believes: that pivoting on the database has the potential to be messy, and it's best dealt with in the application.
Really cool stuff
Great recourse for learning SQL
Thank you ☺️
You have great content
Thanks for the clarity Taufiq! I'm wondering if Crosstab allows date ranges to be selected dynamically. Instead of hard coding the months, is there a way for it to pick up whatever months the data has?
Great explanation sir
Thank you buddy
Thank You 👏👏 great content
Glad you think so!
Hello Sir,
Very good example about transpose method in SQL using PIVOT as well as its equivalent in other RDBMS.
Kindly clarify whether there is any method to make IN part in pivot dynamic instead of hardcoding.
Thank you
Great Video.
Love you. #noHomo.
@techtfq: Of all your videos this one is the most confusing and messy! Just jumping from here to there! Wish you could do more organized considering how good you are in explaining complex matters in simple ways!
Tqsm sir ❤️❤️
Do video to PLSQL real- time querys bro
This video you do is help many persons bro
Great work!
Can we have a content with the comparison of oracle and ms sql ... that helps in migration of entire oracle to ms sql in terms of simple query to stored procedures
Brilliant one Bro. Waiting for Unpivot and Regular Expressions 😅
Thank you and noted bro
Thank you so much! Just a quick note, in oracle we can use coalesce.
Bro kindly make video on regular expressions from scratch till advanced level
Noted bro will consider it
thank you, subbed :)
Amazing work please also share raw data of this amazing problem
Great content tauphik sir, can you please create a separate video like this for unpivot...
Sure bro will do it
One video on data cleaning in sql
Sure bro will do it
in oracle, coalesce is definitely supported! 👍🏽
Thank you buddy
You're welcome ☺️
Hi your videos are very helpful to me and I m begginer bit confused what is the difference between mysql,sql server, oracle,posgresql,plsql can u make a video on it please. Thank you in advance
MMM-YY, Great, some developer in the future will now need to Y3K proof the code. :)
can you make a video on transactions please. Appreciate your work ,Thank you.
Following and enjoying your videos. But in these cases, isn't it just much easier and faster to do these transformations in Excel and import the results into sequel tables for further analysis if needed?
Hi!! Thank you so much for this content, it's very useful and well explained.
I'm trying to do exactly the same query you do on the first part of the video, and for some reason the pivot is not recognizing one of the values in that column. Have you had a similar problem?
Thanks for the explanation. But instead of writing the names of Columns like JAN-21, FEB-21 inside PIVOT I use the function STUFF which does it dynamically. So, we can avoid writing the column names.
Can you please write the syntax ?
@@muhammedsiraj6247 try this.....
1. SELECT @ColumnNames =STUFF(( SELECT DISTINCT ',' + QUOTENAME(PersonType)
FROM databasename FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)'),1,1,'')
2. PRINT @ColumnNames
3. PIVOT (
COUNT(PhoneNumberTypeID)
FOR PersonType
IN (' + @ColumnNames +
')
)
AS PIVOTTABLE'
I have above points in a procedure, I can share the entire code with you. Thanks
@@Beant1980 Hi Beant, can you please share the entire code with us?
Many thanks!
@@yassirnakkach5171 Hi, I have the code written in Microsoft SQL Server for AdventureWorks2016 database. I can email it you the text file?
Hi Beant, can you pls also share the entire code with me pls. Thanks so much
Thanks for the content you put out, Taufiq. One question: can't you put the coalesce/NVL in the base query? Then you wouldn't have to put 12 such statements after the pivot.
Thank you Taufiq. This is really helpful.
I have one quick question. All period which you have used in example and query are kind of static one (Jan21, Feb21 …). How do we make it more dynamic? Meaning, what if we have updated sales data for year 23 or 24… changing period value in query may not be good idea in long run. Any thoughts on this ?
I haven't tried it yet, but can you try to use a query for the "for column value in ()" select and make some kind of distinct month-year in the same query?
In SQL server dynamic pivots are not supported natively. You would need to generate the SQL as a text string and run sp_execute sql on that. It’s a really big missing feature, stops me using pivots at all just not worth the hassle
Good morning sir,next week plz provide on indexes And json
Good Approach, can we have one video on UN Pivot same scenario, and what about if the new month is added it won't be dynamic. Any approach?
It was asked in one of my interview. And I was like yaa allah iske aage bhi kuch hota hai kya
Thanks for the in detail explanation. Can you provide WEBAPI for the same
Hi when will your next batch starts?
Probably in August
would you please deliver a class on clustered and nonclustered indices
Merci
Je vous en prie :)
Hi sir, good work done, please, may we get some videos on TRIGGER in postgresql....? Thanks
Thank you and sure will do
Hi pls tell if recorded lecture available?
and any price benifit compared to live?
Please
hi Sir, one Query. Can we use the pivot command without an aggregate function? Your Suggestions on this please.
Hi tfq can you please upload the video about data validation and performance tuning
Thanks thoufig.. Is it possible make column names are dynamic.. I felt you are hard coding?
Sir, Please mention queries for oracle too
I have already given Oracle query here. Do check the video
@@techTFQ Please try for weekend classes this time🙏🙏
Is there a way to do the reverse of pivoting (unpivot) in mysql? Using no special function
sir can we visualize the data through sql... like can we make graphs by using sql......
Not really,, we generally use visualization tools like power bi or tableau for such things
Hey Taufiq
When are you planning to start fresh sql course ? Looking forward to enrol.
Thanks.
Hello - For some reasons some of the data extracted using crosstab does not align in the columns they are expected to. For example there are 5 columns and one of the records has values for 1, 3 and 5 but when I used crosstab the values for columns 1,3 and 5 goes to columns 1,2 and 3. What should I do to align those data properly? thank you for those who will respond.
Thank you taufiq, i struck in converting columns to rows can you help in doing that please
Can't we use distinct customer in select, add both date and customer in group by, and then use sum(amount)??
Hi sir,kindly let me know Do you have any institution in chennai ?
Sir if you don't mind can you make a video on analytical functions in sql
I have already made it Amulya..
Analytics functions are also called as window function so you can look for window functions videos on my channel
Data passing to Procedure by using
Type table in postgreSql
can you expalin that last part where you are finding the total respective of each column. Please explain the query you used in mysql
Sir one important doubt can we work in company and also post tech videos and tutorials as a freelancer will this be considered dual employment/moonlighting?
Hii can you share the same problem with joins ? I don't exactly have the table but need to get data from different tables. Like 3 or 4 tables
could you please make a video on date related functions