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Data Lineage,

SQL Visualisation Guide – Query Diagrams, Lineage & ERD

Have you ever inherited the SQL codebase from someone else where it is in a “bit of a mess”? 😁 Sound familiar? Most data engineers and SQL developers have been there including myself—staring at a spaghetti-like web of queries, trying to untangle a chaotic SQL codebase. It’s a common nightmare. Traditionally, you had to fight …
Uli Bethke November 3, 2024
SQL,

SQL Challenge: Tackling the Island Problem in Time Series Data

Jump into our SQL Challenge! Today, we're exploring customer loyalty trends. Are you prepared to show off your SQL skills? About the quiz In this SQL pop quiz, we're challenging…
Uli Bethke November 7, 2023
XML,

XML Converters & Conversion – Ultimate Guide (2025)

“Urgent XML Conversion Project – Need by End of Week”. “Just Convert this XML to SQL Tables. Should be Simple!” Sound familiar?  From my experience, XML conversion projects follow the…
Maciek October 4, 2023
Snowflake,

7 guardrails against common mistakes that inflate Snowflake credit usage 

Dodge costly pitfalls Snowflake implementation has pioneered dozens of innovations in the data platform space. The long list includes separation of compute and storage, physical workload separation, data sharing, data…
Uli Bethke September 13, 2023
SQL,

Detect Bad SQL with Static & Dynamic Code Analysis – A Guide

Preventing Query Catastrophe with FlowHigh SQL Analyser Does the following sound familiar? As the wizard EsQuEl delved deep into the SQL code, he stumbled upon multiple instances where tables were…
Uli Bethke September 8, 2023

Recent Articles

All JSON Snowflake XML
Snowflake,

Rocketship Performance for Snowflake with Clustering Keys

Introduction Snowflake stores tables by dividing their rows across multiple micro-partitions (horizontal partitioning). Each micro-partition automatically gathers metadata about all rows stored in it such as the range of values…
Uli Bethke February 8, 2018
Snowflake,

Create your own custom aggregate (UDAF) and window functions in Snowflake

In this post we will show you how to create your own aggregate functions in Snowflake cloud data warehouse. This type of feature is known as a user defined aggregate…
Uli Bethke February 4, 2018
Snowflake,

Learn Window Functions on Snowflake. Become a cloud data warehouse superhero.

In a recent post we compared Window Function Features by Database Vendors. In this post we will give you an overview on the support for various window function features on…
Uli Bethke January 31, 2018
XML,

Converting XML to Hive

In this example we will use the Flexter XML converter to generate a Hive schema and parse an XML file into a Hive database. We will then use the spark-sql…
Maciek January 27, 2018
XML,

How to convert XML to Parquet with Spark

Converting XML to Parquet on Spark might seem straightforward, until you dive in. For years, the go-to approach has been the external spark-xml library: functional, flexible… and a bit hands-on.…
Maciek January 25, 2018
Data Warehouse,

Why is concurrency overrated to measure performance of data warehouse platforms?

The difference between making a good and a bad decisions often comes down to the quality of the pre-defined metrics. If the metric is poor so will be the decision.When…
Uli Bethke January 11, 2018