PrestoDB Questions & Answers

Answers to your questions about PrestoDB

Topics

How do you cross join unnest a JSON array?

November 11, 20202 min read

Let’s take a look at how you can cross join unnest a JSON array by doing Presto joins. Here’s an example using test results data in json form as input, … Continue reading How do you cross join unnest a JSON array?

How can you write the output of queries to S3 easily?

November 10, 20201 min read

With Ahana Cloud, we’ve made it easy for you write output of queries to S3. While there’s a variety of formats, here’s an example:

Does Amazon Athena do joins across other data sources besides S3? Does Amazon Athena connect to other data sources?

November 5, 20201 min read

With Amazon Athena you’re limited in scope when it comes to doing joins across other data sources like relational data systems and more. You have to set up a Lambda, … Continue reading Does Amazon Athena do joins across other data sources besides S3? Does Amazon Athena connect to other data sources?

If I have catalogs connected and configurations attached to my Presto cluster, what happens when I take the cluster down?

November 5, 20201 min read

If you’re managing Presto on your own, either through your own installation or through a service like AWS EMR or AWS Athena, you have to maintain and manage all of … Continue reading If I have catalogs connected and configurations attached to my Presto cluster, what happens when I take the cluster down?

Check If Map Or Presto Array Is Empty Or Contains | Ahana

October 30, 20202 min read

Check if Presto map or array is empty When working with array (indexable lists) or map (key-value tuple) complex types in Presto, it is useful to be able to check … Continue reading Check If Map Or Presto Array Is Empty Or Contains | Ahana

Export Result Of Select Statement | Ahana

October 30, 20203 min read

Export result of Select statement A common question is “how can I run a query and export result of select statement quickly and easily in Presto?”  You are in luck, … Continue reading Export Result Of Select Statement | Ahana

Presto Queries Running Slow | Presto Slow | Ahana

October 23, 20206 min read

Presto queries running slow? There are a few reasons that Presto performance is impacted and queries might be running slow. Below we’ll share some things to do in terms of … Continue reading Presto Queries Running Slow | Presto Slow | Ahana

Extract Keys In A Nested JSON Array Object | Ahana

October 14, 20202 min read

Extract keys in a nested JSON array object Let’s say we have some JSON that looks like this: In this instance our json contains key value pairs. How can we … Continue reading Extract Keys In A Nested JSON Array Object | Ahana

Generate Interval from Variable Using PrestoDB | Ahana

October 14, 20203 min read

Generate Interval from Variable Using PrestoDB There are numerous ways to generate interval from variable using PrestoDB SQL for different data types. Dates Date intervals can be generated for a … Continue reading Generate Interval from Variable Using PrestoDB | Ahana

How To Presto Escape Single Quote | Pesto Escape Quote | Ahana

October 12, 20202 min read

How To Escape a Single Quote With Presto In reality there will be some occasions when you need to use a quote character in your data, in your query, or … Continue reading How To Presto Escape Single Quote | Pesto Escape Quote | Ahana

Check If Null & Return Default (NVL analog) | Ahana

October 3, 20204 min read

Check if null and return default (NVL analog) SQL has a number of functions for dealing with null values, and everyone has their favorite. The complicating factor is that not … Continue reading Check If Null & Return Default (NVL analog) | Ahana

Static Date & Timestamp In Where Clause | PrestoDB Timestamp

October 3, 20202 min read

Static date and timestamp in where clause In this post we’ll look at the static date and timestamp in where clause when it comes to Presto. Many databases automatically convert … Continue reading Static Date & Timestamp In Where Clause | PrestoDB Timestamp

Where Can I Find The Presto Server Bootstrap Logs | Ahana

October 3, 20203 min read

Where can I find the Presto Server Bootstrap logs? A common question is “where can I find the Presto server bootstrap logs?”  These are logs that indicate what is happening … Continue reading Where Can I Find The Presto Server Bootstrap Logs | Ahana

Where Can I Find Different Presto Metrics For Monitoring | Ahana

October 3, 20205 min read

Where can I find different Presto metrics for monitoring? If you’re wondering “Where can I find different Presto metrics for monitoring?”, we’ll help explain it. There are several ways to … Continue reading Where Can I Find Different Presto Metrics For Monitoring | Ahana

Presto Logs | Where Do I Find Presto Logs | Ahana

October 3, 20204 min read

Where do I find Presto logs? If you’re wondering “where do I find Presto logs”, we’ll help explain it. Presto needs a data directory for storing logs, etc. and it … Continue reading Presto Logs | Where Do I Find Presto Logs | Ahana

Presto Equivalent Of mysql group_concat | group_concat Presto

October 3, 20204 min read

Presto equivalent of mysql group_concat PrestoDB supports ANSI SQL and includes support for several SQL dialects, including MySQL dialect, making it easy to group and aggregate data in a variety … Continue reading Presto Equivalent Of mysql group_concat | group_concat Presto

How to get the Presto CLI Tool | Presto-CLI Download | Ahana

September 29, 20204 min read

How to get the Presto CLI Tool The Presto CLI provides a terminal-based interactive shell for running queries. The CLI is a self-executing JAR file, which means it acts like … Continue reading How to get the Presto CLI Tool | Presto-CLI Download | Ahana

Convert Date String to Date Format in Presto | Presto Date Format

September 17, 20204 min read

How To Convert Date String to Presto Date Format PrestoDB supports ANSI SQL and includes support for several SQL dialects, so it’s straightforward to convert a date string to date … Continue reading Convert Date String to Date Format in Presto | Presto Date Format

Where to Find Presto Source Code, and How to Work With it

September 15, 20204 min read

The main branch: PrestoDB source code Presto is an open source project that is developed in the open on the public Github repository: https://github.com/prestodb/presto. The prestodb repo is the original, … Continue reading Where to Find Presto Source Code, and How to Work With it