With the help of SQL MERGE statement, you can perform UPDATE and INSERT simultaneously based on the merge condition. This is especially likely to come up with new Redshift users who are familiar with Postgres and don’t understand how their queries will perform at scale on a Redshift instance. Get a free consultation with a data architect to see how to build a data warehouse in minutes. To create an external table in Amazon Redshift Spectrum, perform the following steps: 1. Redshift is one of the greatest Amazon AWS services which is suitable for Big data, BI and analytics purposes. You may have heard that Redshift is built on Postgres, so they’re basically the same thing. Now that the customer table is created in the AWS Glue Data Catalog, let’s query the table using Redshift Spectrum. You can work with transaction control statements in the PL/pgSQL language that Amazon Redshift uses. Postgres wasn’t originally designed to use more than one core per query. It’s true, they are. Only one statement is allowed at a time, since Redshift can only display one set of results at a time. In order to, say, sum a single column in a million-row table, Postgres needs to read the entire table in order to complete the query. But the benefits of this distributed architecture pretty quickly become apparent when it comes to performance. Create an IAM role for Amazon Redshift. If you’re a Postgres user, you may be used to setting up and storing views--also known as materialized views--for later. AWS Documentation Amazon Redshift Database Developer Guide. Basically, the differences boil down to a few key characteristics: One of the most important distinctions between Redshift and traditional PostgreSQL comes down to the way data is stored and structured in the databases created by the two approaches. The PERFORM statement is: An out-of-line PERFORM statement When procedure-name-1 is specified. For this tutorial, we use a table of weather data. I'm querying a MariaDB installed on an EC2 instance and inserting the records into RedShift from the same EC2 instance that Maria is installed on. You can use any of the mentioned statements in your dynamic query. Learn more about BMC ›. Redshift CASE Statement The Redshift CASE statement selects value from a sequence of conditions based on your requirement, and executes a corresponding statement that matches the evaluated condition. This is great for exploratory data analysis, where analysts might want to get a bird’s eye view of the data by looking at all columns at once to see if any patterns jump out. ©Copyright 2005-2020 BMC Software, Inc.