In this article we explore schema evolution capabilities and limitations in Databricks with regular parquet format and explore schema evolution features and capabilities through delta format with inserts, appends, and overwrites.
2021-06-04
Introduction In my last article, An Introduction to Azure Data Explorer, I discussed the process of creating and using Azure Data Explorer. Azure Data Explorer is mainly used for storing and running interactive analytics on Big Data. First, I need to create the ADX cluster. Then, one or more databases should be created inside the […]
2021-06-02 (first published: 2021-04-09)
25,054 reads
In this article we cover what a Common Table Expression CTE is and how to write a CTE for doing selects, inserts, deletes, updates and more.
2021-06-02
Director at ThoughtWorks Pramod Sadalage explores trends such as rapid digital transformation and an ever-changing tech landscape, that'll change the way we work with databases and DevOps in the next 20 years.
2021-06-02
This article examines how to split a data set for training and testing and evaluating our model using Python.
2021-05-31
9,379 reads
How to create and maintain a 'data dictionary' for your databases, in JSON format, which you can then use to add and update the table descriptions, whenever you build a new version using Flyway.
2021-05-31
Using sequences when scaling up with Oracle RAC presents more issues with contention. In this article, Jonathan Lewis explains how to avoid the problems.
2021-05-31
What's the true and permanent cost of lowering the Fill Factor of an index in SQL Server? It's a lot more than many people think. 9 year SQL Server MVP veteran, Jeff Moden, demonstrates how to calculate the extra space that will be used by lowering the Fill Factor and saved by increasing it.
2021-05-28 (first published: 2019-09-03)
9,977 reads
Database systems have powerful features built right in that can ensure the integrity of data. In this article, Joe Celko discusses keys and constraints.
2021-05-28
Join the world’s largest gathering of data professionals at this year’s free online PASS Data Community SUMMIT. Connect and network with 1000s of your peers and learn from some of the brightest minds in the data industry. This year’s must-attend online event is completely free, so sign up now to be notified when registration opens.
2021-05-28
By Chris Yates
I’m thrilled to be covering the Microsoft Keynote: Fuel AI Innovation with Azure Databases on Day...
By James Serra
Many customers ask me about the advantages of moving from Azure Synapse Analytics to...
By Brian Kelley
The last data centric conference I attended was the PASS Summit in 2019. A...
Hi, In my Always On Availability environment, I am seeing two encrypt_option values as...
Hi everyone I have a bunch of CSV files that I need to bulk...
Comments posted to this topic are about the item What's New for the Microsoft...
I have this data in a SQL Server 2019 database:
Customer table CustomerID CustomerName 1 Steve 2 Andy 3 Brian 4 Allen 5 Devin 6 Sally OrderHeader table OrderID CustomerID OrderDate 1 1 2024-02-01 2 1 2024-03-01 3 3 2024-04-01 4 4 2024-05-01 6 4 2024-05-01 7 3 2024-06-07 8 2 2024-04-07I want a list of all customers and their order counts for a period of time, including zero orders. If I run this query, how many rows are returned?
SELECT c.CustomerName, COUNT(oh.OrderID) FROM dbo.Customer AS c LEFT JOIN dbo.OrderHeader AS oh ON oh.CustomerID = c.CustomerID WHERE oh.Orderdate > '2024/04/01' GROUP BY c.CustomerNameSee possible answers