Skip to main content

Featured post

8 Top Data Science Platform Developers in the World

Top data science tools and platforms providers across the world. Useful information for data science and data analytics developers.

Data Science is a combination of multiple skills. AI and Machine Learning are part of data science. You can create AI and Machine Learning products with data. 

Related Posts

Top Skills You Need for Data Science CareerData Science Sample Project an Example

Spark SQL Query how to write it in Ten steps

Spark SQL example
Spark SQL example
The post tells how to write SQL query in Spark and explained in ten steps.This example demonstrates how to use sqlContext.sql to create and load two tables and select rows from the tables into two DataFrames.

The next steps use the DataFrame API to filter the rows for salaries greater than 150,000 from one of the tables and shows the resulting DataFrame. Then the two DataFrames are joined to create a third DataFrame. Finally the new DataFrame is saved to a Hive table.

1. At the command line, copy the Hue sample_07 and sample_08 CSV files to HDFS:
$ hdfs dfs -put HUE_HOME/apps/beeswax/data/sample_07.csv /user/hdfs
$ hdfs dfs -put HUE_HOME/apps/beeswax/data/sample_08.csv /user/hdfs

where HUE_HOME defaultsto /opt/cloudera/parcels/CDH/lib/hue (parcel installation) or /usr/lib/hue
(package installation).

2. Start spark-shell:
$ spark-shell

3. Create Hive tables sample_07 and sample_08:

scala> sqlContext.sql("CREATE TABLE sample_07 (code string,description string,total_emp
 int,salary int) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' STORED AS TextFile")
scala> sqlContext.sql("CREATE TABLE sample_08 (code string,description string,total_emp
 int,salary int) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t' STORED AS TextFile")

Also Read: Learn SparkSQL by your own with little money

4. In Beeline, show the Hive tables:
[0: jdbc:hive2://hostname.com:> show tables;
+------------+--+
| tab_name |
+------------+--+
16 | Spark Guide
Developing Spark Applications
| sample_07 |
| sample_08 |
+------------+--+

Also read: The role of Spark in Hadoop eco system

5. Load the data in the CSV files into the tables:
scala> sqlContext.sql("LOAD DATA INPATH '/user/hdfs/sample_07.csv' OVERWRITE INTO TABLE
 sample_07")
scala> sqlContext.sql("LOAD DATA INPATH '/user/hdfs/sample_08.csv' OVERWRITE INTO TABLE
 sample_08")

6. Create DataFrames containing the contents of the sample_07 and sample_08 tables:
scala> val df_07 = sqlContext.sql("SELECT * from sample_07")
scala> val df_08 = sqlContext.sql("SELECT * from sample_08")

Apache Spark
7. Show all rows in df_07 with salary greater than 150,000:
scala> df_07.filter(df_07("salary") > 150000).show()
The output should be:
+-------+--------------------+---------+------+
| code| description|total_emp|salary|
+-------+--------------------+---------+------+
|11-1011| Chief executives| 299160|151370|
|29-1022|Oral and maxillof...| 5040|178440|
|29-1023| Orthodontists| 5350|185340|
|29-1024| Prosthodontists| 380|169360|
|29-1061| Anesthesiologists| 31030|192780|
|29-1062|Family and genera...| 113250|153640|
|29-1063| Internists, general| 46260|167270|
|29-1064|Obstetricians and...| 21340|183600|
|29-1067| Surgeons| 50260|191410|
|29-1069|Physicians and su...| 237400|155150|
+-------+--------------------+---------+------+

8.Create the DataFrame df_09 by joining df_07 and df_08, retaining only the code and description columns.
scala> val df_09 = df_07.join(df_08, df_07("code") ===
df_08("code")).select(df_07.col("code"),df_07.col("description"))
scala> df_09.show()

The new DataFrame looks like:
+-------+--------------------+
| code| description|
+-------+--------------------+
|00-0000| All Occupations|
|11-0000|Management occupa...|
|11-1011| Chief executives|
|11-1021|General and opera...|
|11-1031| Legislators|
|11-2011|Advertising and p...|
|11-2021| Marketing managers|
|11-2022| Sales managers|
|11-2031|Public relations ...|
|11-3011|Administrative se...|
|11-3021|Computer and info...|
|11-3031| Financial managers|
|11-3041|Compensation and ...|
|11-3042|Training and deve...|
|11-3049|Human resources m...|
|11-3051|Industrial produc...|
|11-3061| Purchasing managers|
|11-3071|Transportation, s...|
|11-9011|Farm, ranch, and ...|
+-------+--------------------+

9. Save DataFrame df_09 as the Hive table sample_09:
scala> df_09.write.saveAsTable("sample_09")

10. In Beeline, show the Hive tables:
[0: jdbc:hive2://hostname.com:> show tables;
+------------+--+
| tab_name |
+------------+--+
| sample_07 |
| sample_08 |
| sample_09 |
+------------+--+

Comments

Popular posts from this blog

Hyperledger Fabric Real Interview Questions Read Today

I am practicing Hyperledger. This is one of the top listed blockchains. This architecture follows R3 Corda specifications. Sharing the interview questions with you that I have prepared for my interview.

Though Ethereum leads in the real-time applications. The latest Hyperledger version is now ready for production applications. It has now become stable for production applications.
The Hyperledger now backed by IBM. But, it is still an open source. These interview questions help you to read quickly. The below set of interview questions help you like a tutorial on Hyperledger fabric. Hyperledger Fabric Interview Questions1). What are Nodes?
In Hyperledger the communication entities are called Nodes.

2). What are the three different types of Nodes?
- Client Node
- Peer Node
- Order Node
The Client node initiates transactions. The peer node commits the transaction. The order node guarantees the delivery.

3). What is Channel?
A channel in Hyperledger is the subnet of the main blockchain. You c…

Blue Prism complete tutorials download now

Blue prism is an automation tool useful to execute repetitive tasks without human effort. To learn this tool you need the right material. Provided below quick reference materials to understand detailed elements, architecture and creating new bots. Useful if you are a new learner and trying to enter into automation career.
The number one and most popular tool in automation is a Blue prism. In this post, I have given references for popular materials and resources so that you can use for your interviews.
RPA Blue Prism RPA blue prism tutorial popular resources I have given in this post. You can download quickly. Learning Blue Prism is a really good option if you are a learner of Robotic process automation.

RPA Advantages The RPA is also called "Robotic Process Automation"- Real advantages are you can automate any business process and you can complete the customer requests in less time.

The Books Available on Blue Prism 
Blue Prism resourcesDavid chappal PDF bookBlue Prism Blogs

PL/SQL: Popular Reserved Words

Perfect in PL/SQL is an art. To become this you need to understand top reserved words and their meanings. The below list is useful for your projects.


Top List of PL/SQL Reserved Words.. Before you start knowing reserved words, wait one moment. The reserved words all are similar to words that you use in normal SQL. ALL*DESC*ISOLATIONOUTSQLERRMALTER*DISTINCT*JAVAPACKAGESTART*AND*DOLEVEL*PARTITIONSTDDEVANY*DROP*LIKE*PCTFREE*SUBTYPEARRAYELSE*LIMITEDPLS_INTEGERSUCCESSFUL*AS*ELSIFLOCK*POSITIVESUMASC*ENDLONG*POSITIVENSYNONYM*AUTHIDEXCEPTIONLOOPPRAGMASYSDATE*AVGEXCLUSIVE*MAXPRIOR*TABLE*BEGINEXECUTEMINPRIVATETHEN*BETWEEN*EXISTS*MINUS*PROCEDURETIMEBINARY_INTEGEREXITMINUTEPUBLIC*TIMESTAMPINTEGEREXTENDSMLSLABEL*RAISE

Automation developer these are top Skills you need to learn

Robotic process automation is an upcoming IT skill. Three tools are popular. It is difficult to learn all three tool. So, learn anyone tool to start your career in automation.
To get a job in this line, I found in my research that some programming skills and Hand-on training on any one of the tools is required. Also, try to know the differences between popular RPA tools.
Skills Companies Looking in Automation Engineers All big companies looking for candidates having experience in Automation anywhere, Blue Prism and UIPath. It is not possible to learn all tools. Learn anyone tool and do practice well.

Ok.

You may ask a question about how to do it. Join in good training institute and learn one tool.  Take online classes to learn faster.

To learn Uipath try here. Also, you can enroll online course to learn UiPath.

UiPath GO The list of IT skills you needAutomation anywhere/Blue Prism/Uipath .Net/C#/Java/SQL skills MS-Visio Power Builder Python scripts/Unix Scripts/Perl Scripts HTML/CSS/J…

8 Top Data Science Platform Developers in the World

Top data science tools and platforms providers across the world. Useful information for data science and data analytics developers.

Data Science is a combination of multiple skills. AI and Machine Learning are part of data science. You can create AI and Machine Learning products with data. 

Related Posts

Top Skills You Need for Data Science CareerData Science Sample Project an Example

Three popular RPA tools functional differences

Robotic process automation is growing area and many IT developers across the board started up-skill in this popular area. I have written this post for the benefit of Software developers who are interested in RPA also called Robotic Process Automation.


In my previous post, I have described that total 12 tools are available in the market. Out of those 3 tools are most popular. Those are Automation anywhere, BluePrism and Uipath. Many programmers asked what are the differences between these tools. I have given differences of all these three RPA tools.

BluePrism Blue Prism has taken a simple concept, replicating user activity on the desktop, and made it enterprise strength. The technology is scalable, secure, resilient, and flexible and is supported by a comprehensive methodology, operational framework and provided as packaged software.The technology is developed and deployed within a “corridor of IT governance” and has sophisticated error handling and process modelling capabilities to ens…

Top 100 Hadoop Complex Interview Questions (Part 3 of 4)

These are complex Hadoop interview questions. This is my 3rd set of questions useful for your interviews. 1). What are the features of Standalone (local) mode? Ans). In stand-alone mode there are no daemons, everything runs on a single JVM. It has no DFS and utilizes the local file system. Stand-alone mode is suitable only for running MapReduce programs during development. It is one of the least used environments.

2). What are the features of Pseudo mode?
Ans). The pseudo mode is used both for development and in the QA environment. In the Pseudo mode, all the daemons run on the same machine.

3). Can we call VMs as pseudos?
Ans). No, VMs are not pseudos because VM is something different and pseudo is very specific to Hadoop.

4). What are the features of Fully Distributed mode?

Ans). The fully Distributed mode is used in the production environment, where we have ‘n’ number of machines forming a Hadoop cluster. Hadoop daemons run on a cluster of machines. There is one host onto which Namenod…

SQL queries how to use built-in functions correctly

In this post I am giving top examples on SQL functions. About built-in functions, I have covered in my previous post.
List of examples:DATE-TIME functionsNumeric functionsChar functionsNull-related functions1. DATE/TIME functions SELECT p_code, launch_dt, CURRENT_DATE FROM product; CURRENT_DATE returns current date.
SELECT p_code, TO_CHAR(launch_dt, 'DD MONTH YYYY') reformatted_dt FROM product; TO_CHAR function returns DATE in CHAR format.
2. Numeric functions SELECT p_code, price, (price - 20), ABS(price - 20.00) FROM product; ABS - function returns absolute value
SELECT p_code, price, ROUND (price, 1) FROM product;
ROUND function - Round to 1 digit.
SELECT p_code, price, SIGN(price - 15) FROM product;
SIGN function - It returns sign; either + or -
SELECT p_code, price, TRUNC(price, 1) FROM product;
TRUNC function - Truncates to a certain number of decimal places.
3. CHAR functions SELECT p_code, CONCAT(CONCAT(p_name, ' -- ') , price) FROM product; CONCAT function - co…