Recent Articles

SQL,

SQL on Hadoop, BigQuery, or Exadata. Please don’t call them MPP.

I often hear people referring to SQL engines running against HDFS or object storage as MPP. Strictly speaking this is incorrect. Let me first explain what an MPP database is…

Uli Bethke May 10, 2018

SQL,

Comparing Window Function Features by Database Vendors

We will round off the series on window functions with comparison of what database vendors offer. There are various mutations of window functions and every vendor supports a different subset…

Uli Bethke September 15, 2017

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Window Function ROWS and RANGE on Redshift and BigQuery

Frames in window functions allow us to operate on subsets of the partitions by breaking the partition into even smaller sequences of rows. SQL provides syntax to express very flexible…

Uli Bethke August 22, 2017

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Redshift's Window Functions Advanced use case – Sessionization

In the last post about the Window Functions, we introduced an advanced use case, in which the window functions help to make the query more readable, simple and efficient. The…

Uli Bethke August 14, 2017

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Redshift Window Functions Advanced Use Cases

Merging time-based events into periods Thanks to our previous posts about the window functions, Introduction to Window functions on Redshift and Data exploration with Window functions on Redshift, you should…

Uli Bethke August 3, 2017

SQL,

Data Exploration with Window Functions on Redshift

We have already introduced the main concept, syntax and simple examples of window functions applied to practical problems. In this post, we will go through some more advanced window functions…

Uli Bethke July 26, 2017