SQL Join is a clause that is used for combining specific fields from two or more tables based on the common columns available. Joins are used to combine rows from multiple tables. In this article, we will learn about different Redshift join types with some examples. Below are the tables that we will be using to demonstrate different Join types available in Redshift: Students: Id   name   city 1    AAA    London 2    BBB    Mumbai 3    CCC    Bangalore 4    DDD    Mumbai 5    EEE     Bangalore Dept: Did  name    sid 100  CS       1 101 …

Amazon Redshift supports various built in functions, you can use them to extract the numbers, alphanumeric or specific patters from strings. In this article, we will discuss about Redshift extract numbers using regular expressions and examples. In data warehouse environment, you may have different types data files extracted from different data sources. Data might be corrupted or may have unwanted characters, you can clean such a data using Redshift regular expressions. You can read about regular expression in my other post: Redshift Regular Expression Functions and Examples Redshift Extract Numbers…

Like many other relational database or data warehouse appliances, Redshift supports NVL and NVL2 functions. These functions are mainly used to handle the null values in Redshift tables. Redshift NVL Function An NVL expression returns the value of the first expression in the list that is not null. The NVL function replaces a NULL value with a replacement string that you provide in the function as argument. This function returns the first argument if it is not null, otherwise the second argument. The Redshift NVL function is equivalent to the…

Amazon Redshift uses the Massively parallel processing technique, Redshift automatically distributes data and query load across all nodes available in the cluster. In this article, we will check how Redshift distributes table data and importance of right distribution key. How Redshift distributes Table Data? Amazon Redshift uses the three types of distribution; EVEN, KEY and ALL. When you create tables you will have to tell the system which distribution it should use. You may read about distribution types and best practices: Amazon Redshift Distribution Types and Examples If you specify…

A View creates a pseudo-table or virtual table. It appears exactly as a regular table, you can use it in SELECT statements, JOINs etc. A view can be created from a subset of rows or columns of another table, or many tables via a JOIN. Redshift uses the CREATE VIEW statement from PostgreSQL syntax to create View. In this article, we will check Redshift create view syntax and some examples on how to create views. Just like views or table  in other database, a Redshift view contains rows and columns.…

You can use Amazon Redshift hash functions to encode the data by transforming the input into a hash code or hash values. If you use the hash function, no two inputs have same hash values. The hash algorithm are designed to minimize the collision (two inputs having same hash value). You can use the hash function to speed up the data record retrieval by using simple one way lookup. Hash code is used as an index into a hash table which has a pointer to data records. Redshift hash function…