Mysql flatten rows into columns

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mysql flatten rows into columns

Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. See Demo. If you have an unknown number of columnnames that you want to transpose, then you can use dynamic SQL:. This could also be completed using multiple joins, but you will need some column to associate each of the rows which you do not have in your sample data.

But the basic syntax would be:.

mysql flatten rows into columns

This is rather a method than just a single script but gives you much more possibilities. Learn more. Efficiently convert rows to columns in sql server Ask Question.

Asked 7 years ago.

Convert Column Data Fields to Row Data Fields

Active 7 months ago. Viewed k times. A Friend 7 7 silver badges 17 17 bronze badges. Active Oldest Votes. There are several ways that you can transform data from multiple rows into columns.

Using multiple joins This could also be completed using multiple joins, but you will need some column to associate each of the rows which you do not have in your sample data. But the basic syntax would be: select fn. But in the last example, you can use cross join rather than left join because each subquery returns one row. I need to build a dynamic query because I don't know the number of rows. Lets talk about converting a table with I can't use a view for that transformation, what about using a TFV?

I cant recommend it for any production environments but does the job for adhoc BI requests. Bartosz X Bartosz X 1, 17 17 silver badges 28 28 bronze badges. All good until Could not find stored procedure 'dbo.

Any advice? Thanks Bartosz, managed to use some of the ideas from your script and done what I had on my mind already, but nevertheless, thanks for updating it :. I should have thought to change that line, but honestly thought is a stored procedure you've forgot is not default in the system or something like that.

I will give it a run when i get close to that project again, and update here! The Overflow Blog. Podcast Programming tutorials can be a real drag. Featured on Meta. Community and Moderator guidelines for escalating issues via new response…. Feedback on Q2 Community Roadmap. Triage needs to be fixed urgently, and users need to be notified upon….MS SQL. SQL Server has a PIVOT relational operator to turn the unique values of a specified column from multiple rows into multiple column values in the output cross-tabeffectively rotating a table.

It also allows performing aggregations, wherever required, for column values that are expected in the final output. As you can see in the image below, it has sales information for some countries for a couple of years. Also, if you notice, for each country and for each year there is a separate row. Now by using the PIVOT operator, we will convert row values into column values with the script given below and the results as shown in the image below. Though we have used the SUM aggregation function, in this case there is no summation, as there is only one row for each unique combination for country and year.

Please note the use of brackets for pivot column values; these are required. If you notice in the above script, we have provided values, and for pivot columns as these values are available in the original datasets. But what if some additional values are expected to come in the future, for example andetc. In that case, you can still use the pivot column values, which are expected to come or which are still not available in the original dataset in the future though you will see NULL for its values.

The script below shows this scenario and the image below shows NULLs for the years and as there is no data for these years. In that case, you can write a dynamic query to first grab all the unique values for the pivot column at runtime and then a write dynamic query to execute it with the pivot query as shown below:.

Let me demonstrate this with an example; lets create a table with pivoted data from the previous query with the script below. The image below shows data of the newly created table with pivoted data. The image below shows rotated data:. The reason is, Pivot performs aggregation while rotating row values into column values and might merge possible multiple row values into single column value in the output.

For example, consider for a given country and year there are two values, say and Now when you pivot it, the output will have as the column value if you have SUM as the aggregation function. Later if you want to unpivot it back, you will get not the bi-furcated values and as original. Having said that, we can say if the pivoted values are aggregated values, it will not be possible to get the original data back.

I also talked about writing a dynamic query to write a dynamic pivot query in which possible pivot column values are determined at runtime. See all articles by Arshad Ali. Advertiser Disclosure: Some of the products that appear on this site are from companies from which QuinStreet receives compensation. This compensation may impact how and where products appear on this site including, for example, the order in which they appear.

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July 25th, AM.One of the primary functions of a Business Intelligence team is to enable business users with an understanding of data created and stored by business systems. Understanding the data should give business users an insight into how the business is performing. A typical understanding of data within an insurance industry could relate to measuring the number of claims received vs successfully processed claims.

Such data could be stored in source system as per the layout in Table 1 :. Although each data entry in Table 1 has a unique RecKey identifier, it all still relates to a single policy claim policy Pol Thus, a correct representation of this data ought to be in a single row that contains a single instance of policy Pol as shown in Table 2 :.

The objective of this article is to demonstrate different SQL Server T-SQL options that could be utilised in order to transpose repeating rows of data into a single row with repeating columns as depicted in Table 2.

Some of the T-SQL options that will be demonstrated will use very few lines of code to successfully transpose Table 1 into Table 2 but may not necessary be optimal in terms query execution. Script 1 shows how a Pivot function can be utilised. The results of executing Script 1 are shown in Figure 1as it can be seen, the output is exactly similar to that of Table 2.

Furthermore, as we add more policy numbers in our dataset i. Polwe are able to automatically retrieve them without making any changes to Script 1.

Multiple options to transposing rows into columns

This is because the Pivot function works with only a predefined list of possible fields. However, imagine if business later decides to add more documents that are required to process a claim? It would mean that you need to update your Pivot script and manually add those fields.

Thus, although transposing rows using Pivot operator may seem simple, it may later be difficult to maintain. The actual estimated plan depicted in Figure 4indicates that only a single scan was made against the base table with a majority of the cost at Although the general consensus in the professional community is to stay away from SQL Server Cursors, there are still instances whereby the use of cursors is recommended.

Converting Rows to Columns (PIVOT) and Columns to Rows (UNPIVOT) in SQL Server

I suppose if they were totally useless, Microsoft would have deprecated their usage long ago, right? Anyway, Cursors present us with another option to transpose rows into columns. Script 2 displays a T-SQL code that can be used to transpose rows into columns using the Cursor function.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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I have a group of rows in a table that have an id. I am trying to flatten it out in rows with multiple column. I am almost certain I have done this with a cte and maybe partition. I have used cte's to delete duplicate data and I thought I has done something similar to what I am trying to accomplish here. I was able to come up with workable solution listed below but still feel like a more elegant solution should be available.

Learn more. Asked 7 years, 2 months ago. Active 5 years, 9 months ago. Viewed 39k times. DSF 2, 5 5 gold badges 29 29 silver badges 61 61 bronze badges. Active Oldest Votes. You can also use multiple joins on your table: select t1.

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How to convert columns to rows and rows to columns

Stack Overflow works best with JavaScript enabled.I need a way to roll-up multiple rows into one row and one column. I know I can roll-up multiple rows into one row using Pivotbut I need all of the data concatenated into a single column in a single row. In this tip we look at a simple approach to accomplish this. Rolling up data from multiple rows into a single row may be necessary for concatenating data, reporting, exchanging data between systems and more.

This can be accomplished by:. Check out the example below to walk through the code samples and final solution to roll-up multiple rows into a single row in SQL Server. Before we begin, we'll create some tables and sample data which the following script will do for us. Before going to the examples, we need to understand the workings of the commands mentioned above. With this we can insert, replace or remove one or more characters. To do this we can use the STUFF command as follows to replace the first ; in the string with an empty string.

We will use the PATH option, which generates single elements for each row returned. Now that we see what each of these commands does we can put these together to get our final result. For each value from the inner query we are concatenating a ";" and then the actual value to have all of the data from all rows concatenated into one column.

The below is the output for this query. Here is an example that will rollup indexes into one row and show the columns that are part of the index as well as included columns if any exist. There are always several options to complete a task within SQL Server and we should take the time to explore the capabilities offered by the database before developing large and complex code.

I hope this is one more of those examples that shows there are sometimes easier approaches than you think might be available. Post a comment or let the author know this tip helped. All comments are reviewed, so stay on subject or we may delete your comment.

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Your SQL has an error. It will encode the resultting data witht XML markup. Here's the link for the function. Example "D" is what you want. Example "C" is mislabled and isn't what you want. I've a csv file which contains data with new lines for a single row i.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

The reason is that I'm selecting multiple values from multiple tables, and after all the joins I've got a lot more rows than I'd like. As Dag stated in his comment, there is a byte limit on the result. To solve this, run this query before your query:. Of course, you can change according to your needs. To calculate and assign the value:. See the documentation for more details. I found myself wanting to select multiple, individual rows —instead of a group—and concatenate on a certain field.

If you want the total price too, toss in SUM :. See details in the MySQL documantation. In my case I had a row of Ids, and it was neccessary to cast it to char, otherwise, the result was encoded into binary format :. Learn more. Ask Question. Asked 11 years, 5 months ago. Active 11 months ago. Viewed k times. DineshDB 5, 4 4 gold badges 25 25 silver badges 40 40 bronze badges. Dean Rather Dean Rather Active Oldest Votes. My need was to get ALL the data from one column.

Thanks, I didn't know there was group concat length limit. I needed that to get around a monster list I generated. Paul Mougel I think that group by 'all' isn't necessary moreover unwantedbecause this assign to all rows string all and then compare strings between these rows. Am I right? Given: I found myself wanting to select multiple, individual rows —instead of a group—and concatenate on a certain field.

Your hungry-hippo user selects 13, 15, No dessert for her today Find: A way to summarize your user's order in one line, with pure mysql. Even though this is a good answer, this sounds more like advertising than purely answering.

Still a good well-formated answer.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community.

It only takes a minute to sign up. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How to get multiple row data into a row with multiple columns Ask Question. Asked 4 years, 1 month ago. Active 1 year, 6 months ago.

mysql flatten rows into columns

Viewed 19k times. Julien Vavasseur 9, 2 2 gold badges 20 20 silver badges 39 39 bronze badges. Lanw Lanw 81 1 1 gold badge 1 1 silver badge 3 3 bronze badges. Which version of MySQL are you using? What you want is called a pivot, this answer here stackoverflow. Active Oldest Votes. Julien Vavasseur Julien Vavasseur 9, 2 2 gold badges 20 20 silver badges 39 39 bronze badges.

This is an old thread, but what is the performance in doing this, what if I had 15 CASE fields I wanted to inject, and what if there was say ,00o results in the db, using this method, would it have serious performance issues?

Tom V - try topanswers. Sorry, but your answer doesn't answer the question. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.


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