BigData

How to use Impala Replace Function and Examples

The latest version of the Cloudera supports Impala replace function. String manipulation function replace is very much needed in case if you are manipulating strings and when there is a need to replace the particular value. Value could be a junk value or any other values based on your requirements. In this article, we will check Impala replace function and alternative methods that you can use whenever required. Impala Replace Function As mentioned earlier, the latest version of Cloudera impala does provide support for replace function. The syntax and usage…

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July 31, 2019
BigData

Impala Interval Data Type and Conversion Examples

Cloudera Impala Interval type is slightly different compared to Apache Hive interval data types. Only difference is it accept interval unit as a integer, where are in Hive it is string type. Interval type in Impala woks same way as in other relational databases such as Netezza, Vertica, Greenplum, Oracle, etc. In article, we will check more information on Impala interval data type and how to convert it. Impala Interval Data Type Impala interval type syntax accept unit specifications. The unit could be SECOND, HOUR, DAY, MONTH, YEAR. You have…

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July 19, 2019
BigData

How to Update Impala Table? – Steps and Examples

Cloudera Impala and Apache Hive provide a better way to manage structured and semi-structured data on Hadoop ecosystem. Both frameworks make use of HDFS as a storage mechanism to store data. The HDFS architecture is not intended to update files, it is designed for batch processing. i.e. process huge amount of data. But most of the organizations are maintaining a data warehouse on traditional relation databases like Netezza, Teradata, Oracle, etc. When they migrate their data warehouse to Hadoop ecosystem, they might want to have a design similar to that…

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June 18, 2019
BigData

Methods to Access Impala Tables from Python

Apache Impala is an open source massively parallel processing (MPP) SQL query engine for data stored on bigdata Hadoop. Cloudera Impala provides fast, interactive SQL queries directly on your Apache Hadoop data stored in HDFS or HBase. In addition to using the same unified storage platform, Impala also uses the same metadata, SQL syntax (Hive SQL), ODBC driver, and user interface as Apache Hive. In this article, we will check different methods to access Impala tables from python program or script. The methods we are going to discuss here will help you to connect Impala…

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June 4, 2019
BigData

Impala Delete from Tables and Alternative Steps

Data warehouse stores the information in the form of tables. You may have to delete out-dated data and update the table’s values in order to keep data up-to-date. These performance critical operations are critical to keep the data warehouse on bigdata also when you migrate data from relational database systems.  In this article, we will check Impala delete from tables and alternative examples. Impala Delete from Table Command Cloudera Impala version 5.10 and above supports DELETE FROM table command on kudu storage. This command deletes an arbitrary number of rows…

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June 2, 2019
BigData

SQL SET Operator MINUS Alternative in Impala

The SQL set operators are used to combine data from two or more SELECT statements. The set operators can combine only similar data sets. Here similar data set literally means the number of columns and its data type should match, otherwise you must explicitly type cast the types of the values or columns in the SELECT statements. Just like Apache hive, Impala support only UNION and UNION ALL set operator, INTERSECT and MINUS are not supported as of now. In this article, we will check SQL set operator MINUS alternative…

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May 31, 2019
BigData

Cloudera Impala Merge Statement – UPSERT Command

The MERGE query or statement in SQL is used to perform incremental load. With the help of SQL MERGE statement, you can perform UPDATE and INSERT simultaneously based on the condition. i.e. you can update old values and insert new records. The merge command is widely used in incremental load where you have to update old records and insert new records if any. In this article, we will check Cloudera Impala Merge Statement along with some Impala native UPSERT command. In SQL world, the merge statement is also referred to…

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May 30, 2019
BigData

Impala Dynamic SQL Support and Alternative Approaches

Dynamic SQL lets SQL statements be created and execute at run time, i.e. you can build SQL queries based on the user or application input and execute them to provide required output. For examples, pass a session specific value to the Impala queries dynamically during runtime. In this article, we will check how to build Cloudera Impala Dynamic SQL queries and how to execute them. Most of the relational databases like Netezza, Teradata, etc. supports stored procedure that will allow you to build and execute dynamic queries. Impala Dynamic SQL…

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May 29, 2019
BigData

Cloudera Impala Extract Function and Examples

Cloudera extract function returns one of the numeric date or time fields from a TIMESTAMP value. Cloudera Impala extract function extracts the sub field represented by units from the date/time value, interval, or duration specified for column. This function is equivalent to Impala date_part() function but parameters reversed. In this article, we will discuss on Impala extract function and its usage with some examples. Cloudera Impala Extract Function Syntax The extract function complies with SQL-99 standard function. The syntax for extract function is same as other RDBMS extract functions. Below…

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January 10, 2018
BigData

Impala Create External Table, Syntax and Examples

A Impala external table allows you to access external HDFS file as a regular managed table. This operation saves resources and expense of importing data file into Impala database. You can perform join using these external tables same as managed tables. You can write complex queries using these external tables. In this article, we will check on Impala create external table with some examples. Syntax for creating impala external table is same as creating managed tables. There is one exception to this, LOCATION option is mandatory for creating external tables. LOCATION…

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January 9, 2018