Category: Hive explode array to columns

idea final, sorry, but all does not..

Hive explode array to columns

Sai Satish you can achieve it in this way. View solution in original post. I am looking for multiple array columns solution. What if my table contains more than one array column if i use Lateral view explode in my Hive query it results Cartesian product. I am using Hive version is - 1. Were you able to solve this?

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Labels: Apache Hive. Reply 9, Views. Tags 6. Tags: Data Processing. Accepted Solutions.I know about explode but i did not understand the output of above query. A lateral view first applies the UDTF to each row of base table and then joins resulting output rows to the input rows to form a virtual table having the supplied table alias.

A lateral view first applies the UDTF to each row of base table means it will return. I have found some simple articles on this topic please go through following links. Hope it will be useful for you. How 1 will match with [1,2,3].

The thing to see here is that this query is a cross product join between the tables tf1 and tf2. The original question used "AS" syntax, which automatically maps the generated table's columns to column aliases.

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In my view it is much more powerful to leave them as tables and use their fully qualified table correlation identifiers. Support Questions.

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Showing results for. Search instead for. Did you mean:. Alert: Welcome to the Unified Cloudera Community. Former HCC members be sure to read and learn how to activate your account here. All forum topics Previous Next. Labels: Apache Hive. In manual:- A lateral view first applies the UDTF to each row of base table and then joins resulting output rows to the input rows to form a virtual table having the supplied table alias.

A lateral view first applies the UDTF to each row of base table means it will return 1 2 3 3 4 5 and then joins resulting output rows to the input rows to form a virtual table having the supplied table alias.? Reply 69, Views. Tags 3.

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Tags: Data Processing. Any Input on this? Reply 14, Views. Hi Vamsi, I have found some simple articles on this topic please go through following links. Thanks, Mahesh. Thanks for input but still having clarification on below point. A lateral view first applies the UDTF to each row of base table and then joins resulting output rows to the input rows to form a virtual table having the supplied table alias A lateral view first applies the UDTF to each row of base table means it will return 1 2 3 3 4 5 and then joins resulting output rows to the input rows to form a virtual table having the supplied table alias.?

To take an example: select tf1. These tables can be used in joins as well: select tf1. Already a User?

hive explode array to columns

Sign In. Don't have an account?By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I found a very good solution to this problem without using any UDF, posexplode is a very good solution :. You can do this by using posexplode, which will provide an integer between 0 and n to indicate the position in the array for each element in the array.

Then use this integer - call it pos for position to get the matching values in other arrays, using block notation, like this:. This avoids the using imported UDF's as well as joining various arrays together this has much better performance. Note - In the above statements, if you place - select cookie,myprod,mycat,myqty from table in place of select cookie,productid[myprod],categoryid[mycat],qty[myqty] from table in the output you will get the index of the element in the array of productidcategoryid and qty.

Hope this will be helpful. How are we doing? Please help us improve Stack Overflow. Take our short survey. Learn more. Asked 6 years, 3 months ago. Active 1 year, 10 months ago. Viewed 40k times. Active Oldest Votes.

Jerome Banks Jerome Banks 1, 9 9 silver badges 14 14 bronze badges. I'm not sure different array sizes would make sense. Then you would have to check if n was larger than the current array. Something like. Hey this works! I guess with the caveat that your arrays need to have the same length, and if they don't it's going to truncate them to the length of the shortest one.

I'm not sure on the performance of this either, especially with more and more lateral views. Then use this integer - call it pos for position to get the matching values in other arrays, using block notation, like this: select cookie, n.

I tried to work out on your scenario Venantius 2, 2 2 gold badges 21 21 silver badges 32 32 bronze badges. Lakshman Purihella Lakshman Purihella 1.

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Post as a guest Name. Email Required, but never shown. The Overflow Blog. Q2 Community Roadmap. The Unfriendly Robot: Automatically flagging unwelcoming comments. Featured on Meta.Hive allows you to emit all the elements of an array into multiple rows using the explode UDTF, but there is no easy way to explode multiple arrays at the same time. Say you had an ordered list of multiple values, possibly of different types.

Then you need to have to explode the arrays, and have a row which contains the values from the two arrays. It emits an integer according to a specified numeric range. It takes 1,2 or 3 arguments. For 1 argument, it emits an integer from 0 to n For 2, it emits from the first argument to the second argument value — 1. For 3, it uses the third argument as an increment value. But suppose if we want to explode array at level 1 and level 2, how should we do that? Since array size will be different in this case.

For nested structures, maybe you can just do multiple lateral views?

Pivot rows to columns in Hive

Hive should be able to do that. Could you post details to your question to stackoverflow, and we can see if Brickhouse can help out in that usecase? However, if the attribute values are missing, some of the arrays have varying lengths so I get the wrong attributes in the wrong rows.

Hive Complex Data Types Tutorial - Hive Complex Data Types Example - Hive Complex Queries

Also, if I have this:. Then you could do 2 lateral view explodes for each of the different arrays. Joe 20 I want to know if there is a function that works like explode function but the desired output would be in columns NOT rows.

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Joe 72 Kay, Hive needs to know the size of the array ahead of time, because each row needs the same number of columns. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account.

You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. Brickhouse Confessions. Skip to content. Home About Brickhouse. Share this: Twitter Facebook LinkedIn.In this blog, we will discuss the working of complex Hive data types.

Before we move ahead you can go through the below link blogs to gain more knowledge on Hive and its working. Generally, in Hive and other databases, we have more experience on working with primitive data types like: Numeric Types.

Apart from these primitive data types, Hive offers some complex data types which are as listed below: Complex Data Types.

Thus, let us know what are these complex data types and their working in Hive. So, in our example, we will be using our Hive default database to store the complex data type tables. The first complex type is an array. It is nothing but a collection of items of similar data type. In our Array example, we will be using the dataset Temperature. Date State Temperature [Depending on their district level wise] So, let us create a table to store the above values of dataset Temperature using below code.

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To check the schema of the table Temperature we can use the command describe Temperature; Now, let us load our input dataset Temperature. To select a column and a value from the table we can use the below command. So, we can follow the above steps to work with complex data type array values in Hive. Now, let us know what is Map and its working.

In our Map example we will be using the dataset Schools. So, let us create a table to store the above values of dataset Schools using the below code. Here, year represents the key and the subsequent data represents the value.

To select a column and its key value from the table we can use the below command.

hive explode array to columns

So, we can follow the above steps to work on a collection Map Key value pairs in Hive. Now, let us know what is Struct and its working. Struct is a record type which encapsulates a set of named fields that can be any primitive data type. In our Struct example, we will be using the dataset Bikes. So, let us create a table to store the above values of dataset Bikes using below code. To check the schema of the table MySchools we can use the command describe MyBikes; Now, let us load our input dataset Bikes.

To select a Struct column values from the table we can use the below command. EngineType from MyBikes; To select a column and its Struct column values from the table we can use the below command. We can observe from the above image we are using Dot.

Types column values from the table. We hope this post has clarified the concept of Bucketing in Hive. Enroll for Big Data and Hadoop Training conducted by Acadgild and become a successful big data developer.Suppose, you have one table in hive with one column and you want to split this column into multiple columns and then store the results into another Hive table. Insert data into connections columns, String should be comma separated.

For e. Create an output table where you want to store split values. Run below command in the hive:. There is a built-in function SPLIT in the hive which expects two arguments, the first argument is a string and the second argument is the pattern by which string should separate.

It will convert String into an array, and desired value can be fetched using the right index of an array. Inner query is used to get the array of split values and the outer query is used to assign each value to a separate column.

What should i do for that? You must be logged in to post a comment. Split one column into multiple columns in hive In: Hive. Share Tweet LinkedIn. Subscribe to our newsletter.

Leave a Reply Cancel reply You must be logged in to post a comment. Load CSV file in hive Requirement If you have comma separated file and you want to create a table in the hive on top of it Split one column into multiple columns in hive Requirement Suppose, you have one table in hive with one column and you want to split this column in This file contains some empty tag.

Partitioning in Hive Requirement Suppose there is a source data, which is required to store in the hive partitioned table The requirement is to load JSON Export hive data into file Requirement You have one hive table named as infostore which is present in bdp schema. One more appl Join in pig Requirement You have two tables named as A and B and you want to perform all types of join in Pig.

String to Date conversion in hive Requirement: Generally we receive data from different sources which usually have different types of Pass variables from shell script to hive script Requirement You have one hive script which is expecting some variables. The variables need to be pas The file format is a text format.

hive explode array to columns

The requirement Pass variables from shell script to pig script Requirement You have one Pig script which is expecting some variables. The variables need to be pass Load tsv file in pig Requirement Assume that you want to load TSV tab separated values file in pig and store the output Load pipe delimited file in pig Requirement Assume that you want to load file which have a pipe separated values in pig and sto Load xml file in pig Requirement Assume you have the XML file which is transferred to your local system by some other app Load hive table into spark using Scala Requirement Assume you have the hive table named as reports.Hive supports array type columns so that you can store a list of values for a row all inside a single column, and better yet can still be queried.

This is particularly useful to me in order to reduce the number of data rows in our database. You can see that it has saved me one record in this instance. Of course it is not big deal, but with hundreds of millions of rows of data, it will have great impact. Another advantage of saving data in this format is that you can selectively get the data you want and then expand them again to the original format.

You can get more information from the official Hive Wiki page. I totally overlooked your update, apologies. Hi Eric, Nice explanation. Could you explain how to achieve the converse of this i. Please try again by adding the missing table name and let me know how you goes. Thanks for visiting my blog. Thanks a lot for your visit and your pick up of my typo on the blog. I have updated it with correct wording.

Hey Eric, thanks for the blog. I had a doubt. If we have json string stored in one of the column. Within the json string, there are many fields, and one of the field is a comma separated array of strings say str1, str2, str3…. How to access the entities within these str1, str2 ,str3. The table contains the example json-type strings in a column. What will be the give query for that? Your email address will not be published. Save my name, email, and site URL in my browser for next time I post a comment.

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Hi Anju, Thanks for visiting and I am glad that my article helps. Hi sgad, Thanks for your comment. Is it possible if you can share the detailed steps to achieve this? Thanks again. Hi Jaise, Thanks for visiting my blog. Did you mean to group a list of values into array? Hope above helps. Hi Vinod, Sorry about the delay. Hi Eric, Thanks for information. Br, Maruthi. Hi Kishore, Thanks for visiting my blog. Hi CSmith, Thanks a lot for your visit and your pick up of my typo on the blog.

Thanks again!


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