Amazon Redshift is fully managed, distributed, petabyte scale relational database system on Amazon web services (AWS). Redshift is a columnar database, it is capable of performing complex queries efficiently over petabytes of data. You can scale the database based on your needs and handle growing datasets. Redshift comes with built-in query optimization features. As a part of performance enhancement step, you can distributes table data on particular column(s). Another important feature is the Redshift sort key to boost your Redshift data access mechanism. In this article, we will check how…

When you work on the different data sources and trying to load data to Redshift from multiple sources, you might encounter type cast issues such as characters in integer column and that leads the loading to fail. Hence, it is very important to perform integer value check when you are not sure about source data types. In this article, we will check how to performance integer value check in Redshift database. Why you should check for Integer values in Redshift? When you are working on the data warehouse and heterogeneous…

Amazon Redshift LEFT and RIGHT functions are string functions which are useful when you want to get sub-string from the given raw string. For example, consider a fixed width file and you want to extract leftmost 10 numbers, you can use Redshift LEFT function with length as an argument. In this article, we will check Redshift LEFT and RIGHT functions with some examples. Redshift LEFT and RIGHT Functions Page Contents Introduction to Redshift String Functions Amazon Redshift Left and Right Functions Redshift LEFT Function Redshift RIGHT Function Redshift SUBSTR as…

The MERGE command or statement in standard SQL is used to perform incremental load. i.e. load only new set of records into target table. With the help of SQL MERGE statement, you can perform UPDATE and INSERT simultaneously based on the merge condition. As of now, Amazon Redshift doesn't support a single merge statement. In this article, we will check what is Redshift merge statement with an example. Merge table or Update insert is also called UPSERT. Page Contents Introduction to Amazon Redshift. Understanding the Merge Statement Merge Statement in Amazon Redshift…

The Redshift pad functions are string functions used to remove or add the string at the beginning or at the end of the expression. An expression could be a column value from your Redshift database or schema table. In this article, we will check Redshift pad zeros using built in pad functions. Page Contents Introduction to Redshift String Functions Amazon Redshift LPAD and RPAD Functions Redshift LPAD Function Redshift RPAD Function Amazon Redshift LPAD and RPAD Examples Benefits of LPAD and RPAD functions in Redshift Conclusion Introduction to Redshift String…

A subquery in a database is a select expression that is enclosed in parentheses as a nested query block in a query statement. The Subquery may return zero to one or more values to its upper select or parent select statements. In this article, we will check Redshift type of subqueries with an examples. Redshift Subqueries Page Contents Introduction to Amazon Redshift Subqueries Redshift Type of Subqueries Best Practices for Redshift Subqueries Conclusion Introduction to Amazon Redshift Subqueries A subquery in Redshift is a nested select statement, that return zero…

Redshift Correlated subquery is a query within a query that refer the columns from the parent or outer query. This kind of subquery contains one or more correlations between its columns and the columns produced by the outer query. Redshift does support the regular and correlated subqueries. In most cases, the Redshift correlated subqueries are used to improve the SQL query performance. Page Contents Introduction to Redshift Correlated Subquery What is Redshift Correlated Subquery? Examples of Redshift Correlated Subquery Redshift Correlated Subquery Performance Considerations Redshift Correlated Subquery Restrictions Conclusion Introduction…