Comparing Window Function Features by Database Vendors

Jiří Mauritz September 15, 2017

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 or feature. Some also add extra window functions or features beyond standard ANSI SQL. One of the most powerful features is user-defined aggregate functions (UDAF), ...

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Window Function ROWS and RANGE on Redshift and BigQuery

Jiří Mauritz August 22, 2017

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 definitions of a frame. We described the syntax in the first post on Window functions and demonstrated some basic use cases in the post on ...

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Query Offload with Redshift Spectrum. Use Cases and Limitations

Jiří Mauritz August 17, 2017

Update: An earlier version of this article claimed that Spectrum runs Presto under the hood. This is incorrect. Spectrum uses its own query layer. Query offload from relational data warehouses to cheaper distributed storage seems to be all the rage these days. In this blog post we examine what works and what the limitations are. ...

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Redshift's Window Functions Advanced use case – Sessionization

Jiří Mauritz August 14, 2017

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 problem was to find free call intervals for each customer, which are created as customers tops-up their credit for at least €20 and get free ...

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