How to convert rows into columns in sql query

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How to convert rows into columns in sql query

how to convert rows into columns in sql query

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.

how to convert rows into columns in sql query

Polwe are able to automatically retrieve them without making any changes to Script 1. 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.

How to transpose column to row in sql

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.

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. Execution of Script 2 lead to the result set displayed in Figure 6 yet, the Cursor option uses far more lines of code than its T-SQL Pivot counterpart.

Similar to the Pivot function, the T-SQL Cursor has the dynamic capability to return more rows as additional policies i. Pol are added into the dataset, as shown in Figure 7 :. The major limitation of transposing rows into columns using T-SQL Cursor is a limitation that is linked to cursors in general — they rely on temporary objects, consume memory resources and processes row one at a time which could all result into significant performance costs.

Thus, unlike in the Pivot function wherein the majority of the cost was spent sorting the dataset, the majority of cost in the Cursor option is split between the Sort operation at The version of the script that uses XML function to transpose rows into columns is shown in Script 3.

Pol are retrievable in the XML option without having to update the original script. Furthermore, the XML option is also able to cater for dynamic field names i. The execution plan of Script 3 is almost similar to that of the Pivot function script in that majority of the cost is taken up by the Sort operator with the Table scan being the second most costly operation. Again, like all the other options, the script using Dynamic SQL returns data in a correctly transposed layout.

It is not surprising then that its execution plan and operations tree will look almost similar to that of the XML option. The Pivot option was shown to be the simplest option yet its inability to cater for dynamic columns made it the least optimal option.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. Any ideas how to achieve the same in SQL View? You are not explaining why your PIVOT query did not work for you, although it is not too hard to guess if your Response sample is representative enough of the data in that table in general.

You have two sets of responses for User 2 but your query picks up only one. As your expected output shows you want the query to return both sets, you need to teach it to distinguish between various sets of answers by the same user. If there are special cases in the real data e. I've done something similar in MySQL but I'm sure you could make some changes to make it work for your need. Sign up to join this community.

The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How to convert Rows to Columns Ask Question.

how to convert rows into columns in sql query

Asked 3 years, 4 months ago. Active 3 years, 4 months ago. Viewed 17k times. I've a table Columns and a second table Response in which all data is saved. UserId ,R. TextC. Sid M Sid M 1 1 gold badge 1 1 silver badge 5 5 bronze badges. I don't know - how there start chat, because code in comment look bad, but it not full answer so not ready public it as final answer select R. Active Oldest Votes. UserId, r.

Text, c. Id FROM dbo. Response AS r ON c. Andriy M Andriy M Please try to add some details to the answer, it will help more. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.

Convert Rows into Columns using SQL Server PIVOT

Email Required, but never shown. The Overflow Blog. Podcast Cryptocurrency-Based Life Forms. Q2 Community Roadmap. Featured on Meta. Community and Moderator guidelines for escalating issues via new response…. Feedback on Q2 Community Roadmap.Usually, we PIVOT a table using unique values extracted from a column and show the result in multiple columns.

As usual, we will use the dbo. Books table for our demo. The table has five columns and few rows in it. Hope, you have checked the above link, and created the table and inserted the rows.

Also, check this list of popular SQL Server post in our blog.

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We looked for unique values in Category column and used the list in our query as columns. Now, an obvious question comes to our mind. It is not always wise to hardcore values as columns. Since, categories might change in the Books table or we add new categories to the list.

We will first extract all the Distinct categories from the table and store the result in a variable. Each value is separate by a comma. We got the values for our columns, all separate by a comma.

Switching rows and columns in SQL

The matter gets worse when company auditors complain about irregularities in the balance sheet etc. We are talking about an SQL query, which will transform records from multiple rows into columns. Bulk upload requires inserting multiple rows of data in a table. Every day sales is stored in the table with columns such as date, quantity, price etc. I want to get the total sales for every month. Find out how this is done in SQL Server. To make it simple, it is like searching a specified character or characters in a string.

Please enable JavaScript to view this page properly. Ever wondered how you can convert data from rows to columns in SQL Server. Computers Category Business, Computers, Programming, Science. Business Like this Article? Subscribe now, and get all the latest articles and tips, right in your inbox.

Delivered by FeedBurner.So how do you swap colums and rows in an aggregate table? Do you really need to use a CLR routine for this? Recently, I came across a description of a transformation operation using SQL Server CLR — the goal is to convert, or transpose, columns into rows and rows into columns.

The problem was to replicate this sort of functionality in SQL Server. In the example of the CLR transform function, the source data included columns for PaymentDateand three types of payments:. Once transformed the result would swap the columns and rows to this configuration:. The following script creates the test table and populates it with the sample test data:. The root cause behind this transformation is that the three payment columns violate first normal form. Column names that include data Medicare, Medicaid, VA is clear indication that first normal form is being ignored with repeating columns.

Had the source data been properly normalized there would been no need to transform the columns and rows. If you find yourself needing to perform this type of transformation regularly, then you have a problem with your schema design. A normalized version of the source table should have columns for PaymentDatePaymentTypeand Amount. The key is recognizing that the source data violated first normal form, and that the unpivot command is designed specifically to normalize this type of unnormalized data.

In the query below, the sq subquery first uses an unpivot command to normalize the data which is then passed to the pivot command in the outer query.

Pairing the unpivot and pivot command makes quick work of the transformation task. We make some assumptions about the nature of the data when we use the MIN aggregate function. The routine expects to ignore duplicate entries for a particular PaymentDate if there are any.

Before SQL Serveryou would have had to use the slightly more convoluted code …. The example provides two lessons for SQL server designers and developers. As well as offering advanced IntelliSense-style code completion, full formatting options, object renaming, and other productivity features, SQL Prompt also offers fast and comprehensive code analysis as you type. Try it free. Fortnightly newsletters help sharpen your skills and keep you ahead, with articles, ebooks and opinion to keep you informed.

Paul has been developing data-centric solutions sinceand was the Enterprise Data Architect for Compassion International, a SQL Server instructor with Learning Tree, the technical editor for a database magazine, and a U. View all articles by Paul Nielsen.

Federal Healthcare Managed Service Providers. Home SQL. In the example of the CLR transform function, the source data included columns for PaymentDateand three types of payments: Once transformed the result would swap the columns and rows to this configuration: The following script creates the test table and populates it with the sample test data:.

Use tempdb .So how do you swap colums and rows in an aggregate table? Do you really need to use a CLR routine for this? Recently, I came across a description of a transformation operation using SQL Server CLR — the goal is to convert, or transpose, columns into rows and rows into columns.

The problem was to replicate this sort of functionality in SQL Server. In the example of the CLR transform function, the source data included columns for PaymentDateand three types of payments:. Once transformed the result would swap the columns and rows to this configuration:. The following script creates the test table and populates it with the sample test data:. The root cause behind this transformation is that the three payment columns violate first normal form.

Column names that include data Medicare, Medicaid, VA is clear indication that first normal form is being ignored with repeating columns. Had the source data been properly normalized there would been no need to transform the columns and rows. If you find yourself needing to perform this type of transformation regularly, then you have a problem with your schema design.

A normalized version of the source table should have columns for PaymentDatePaymentTypeand Amount. The key is recognizing that the source data violated first normal form, and that the unpivot command is designed specifically to normalize this type of unnormalized data. In the query below, the sq subquery first uses an unpivot command to normalize the data which is then passed to the pivot command in the outer query.

Pairing the unpivot and pivot command makes quick work of the transformation task. We make some assumptions about the nature of the data when we use the MIN aggregate function. The routine expects to ignore duplicate entries for a particular PaymentDate if there are any. Before SQL Serveryou would have had to use the slightly more convoluted code …. The example provides two lessons for SQL server designers and developers. As well as offering advanced IntelliSense-style code completion, full formatting options, object renaming, and other productivity features, SQL Prompt also offers fast and comprehensive code analysis as you type.

Try it free. Fortnightly newsletters help sharpen your skills and keep you ahead, with articles, ebooks and opinion to keep you informed. Paul has been developing data-centric solutions sinceand was the Enterprise Data Architect for Compassion International, a SQL Server instructor with Learning Tree, the technical editor for a database magazine, and a U.

View all articles by Paul Nielsen. Federal Healthcare Managed Service Providers. Home SQL. In the example of the CLR transform function, the source data included columns for PaymentDateand three types of payments: Once transformed the result would swap the columns and rows to this configuration: The following script creates the test table and populates it with the sample test data:.

Use tempdb. PaymentDate Date Not Null. VA INT. MedicareMedicaidVA. MIN Amount. FROM Payment. Subscribe for more articles Fortnightly newsletters help sharpen your skills and keep you ahead, with articles, ebooks and opinion to keep you informed.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.

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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:.

Convert Rows into Columns using SQL Server PIVOT

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.

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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.

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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.

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How to Convert Rows to Columns and Back Again with SQL (Aka PIVOT and UNPIVOT)

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. This is my query output:. Though wanting a different set of values called "ServiceName" in the output might be confusing for consumers of the query. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered.

How to convert rows into columns in sql server using pivot or with out pivot Ask Question. Asked 3 years, 2 months ago. Active 2 years, 6 months ago. Viewed 4k times. How to convert rows into columns in sql server? This is my query output: I need like. Surendra Surendra 13 1 1 silver badge 5 5 bronze badges. Share DDL of the tables. Did you get some errors or bad results? Where on earth does QuoteServiceID come from?

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Can you make sure the DDL and sample code you posted actually works as posted? Active Oldest Votes. I assumed that this is all of the data. You have to explicitly name the columns twice, and the ServiceName values once. If you have 40 more service names and a bunch of additional measurement columns, you can use dynamic SQL to build those commands - but that is an order of magnitude more complicated. There is no straightforward way to get the ordering you showed in the question - the un pivoting will yield seemingly arbitrary results that don't match the physical ordering of the columns in the table.

You can use a CASE expression or charindex against a hard-coded list, but you'd have to manually specify the columns a 3rd time.

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