Redshift

Set Operators in Redshift: UNION, EXCEPT/MINUS and INTERSECT

Like many other cloud data warehouses, Amazon Redshift supports set operators such as UNION, EXCEPT/MINUS and INTERSECT to combine two or more similar data sets from two or more SELECT statements. Here the similar data set literally mean, the data type of the result set should also match, otherwise you have to explicitly type cast data when using Redshift set operators. Set Operators in Redshift Types of Set Operators in Redshift Amazon Redshift supports the following types of set operators: UNION [DISTINCT] and UNION ALLINTERSECT [DISTINCT]EXCEPT [DISTINCT] or MINUS [DISTINCT]…

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April 6, 2022
Redshift

Working with Redshift Regular Expression Functions

The regular expression functions in Amazon Redshift offer many advantages such as identifying precise patterns of characters in the given string. You can use these functions to validate the input data. For e.g. validate if the input value is an integer. The regular expression can also help you to extract specific string or characters from input. Redshift Regular Expression Functions In the previous post, we have discussed Redshift NVL and NVL2 functions to deal with NULL values. In this article, we will check how to use Redshift RegEx functions in…

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April 4, 2022
Redshift

Redshift NVL and NVL2 Functions – Syntax and Examples

In my other post, we have discussed how to handle NULL values in Redshift using NULL handling functions. In this article, we will check couple of NULL handling functions such as Redshift NVL and NVL2 functions in details with syntax, usage and few examples. Redshift NVL and NVL2 Functions Redshift NVL and NVL2 Functions Similar to many other relational database or data warehouse appliances, Redshift supports NVL and NVL2. These functions are mainly used to handle the null values in Redshift tables. For example, replace NULL values with any readable…

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March 9, 2022
Redshift

How to Handle NULL in Redshift? – Functions

A NULL value in a relational database is a special marker in SQL that indicates a data value does not exist in the database table. In other words, it is just a placeholder to denote values that are missing or that we do not know. Almost all relational databases and bigdata frameworks support functions to handle null values. In this article, we will check how to handle NULL in Amazon AWS Redshift, we shall also check Redshift NULL handling functions, usage and some examples. Handle NULL in Redshift Handle NULL in Amazon Redshift Similar…

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March 9, 2022
Redshift

Working with External Tables in Amazon Redshift

Until recently Amazon Redshift was not supporting external tables. But, you can create external tables in Amazon Redshift using Redshift Spectrum. External tables allow you to access S3 flat files as a regular Redshift table. You can join the Redshift external table with a database tables such as permanent or temporary table to get required information. You can also perform a complex transformation involving various tables including external tables. The External tables are usually used to build the data lake where you access the raw data file which is stored…

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March 2, 2022