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Tag Archive: Merge

  • Combining Queries from Multiple Sources in Power BI using Merge and Append

    March 1st, 2022 in Azure, Blog, Business Intelligence, Power BI, Power Query, SQL Server, Uncategorized

    It is always good practice to do as much data preparation as close to the sources as you can before importing or connecting them to your Power BI reports, but what if there are circumstances where this isn’t possible? I had an issue recently where a third-party application had been updated and both the new and legacy versions were being used side-by-side. Logging data from both versions was being written to two separate Azure SQL databases.…

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  • MSc Dissertation – Performance of Loading SCDs in SSIS

    July 20th, 2012 in Blog, Business Intelligence, Integration Services, SQL Server

    Well after 3.5 years, I’ve finally completed my MSc Business Intelligence – hoorah! And to reward the time, effort and increased grey hair, they saw fit to give me a merit as well. During the last year I’ve been writing a thesis investigating the performance characteristics of loading data into data warehouse dimensions. Specifically loading Type 2 SCDs using SSIS. For those who have followed the previous posts and my…

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  • SQLBits X Video available

    June 19th, 2012 in Blog, Business Intelligence, Community, Integration Services, SQL Server

    SQLBits X Video Now available The video of my talk at SQLBits X is now available on the SQLBits website here. The talk was focused on presenting the results of my MSc Business Intelligence dissertation, comparing the performance of different methods of using SSIS to load data warehouse dimensions, specifically type 2 SCDs. The talk also covers a comparison of the performance between traditional hard disks and solid state storage systems such as…

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  • Automating T-SQL Merge to load Dimensions (SCD)

    April 6th, 2012 in Blog, Business Intelligence, Integration Services, SQL Server

    This is the 3rd post in the Frog-Blog series on the awesomeness of T-SQL Merge. Post 1: Introduction to T-SQL merge basics Post 2: Using T-SQL merge to load data warehouse dimensions In this post we’ll be looking at how we can automate the creation of the merge statement to reduce development time and improve reliability and flexibility of the ETL process. I discussed this in the 2nd half of a talk I gave at the UK technical launch of SQL…

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  • Using T-SQL Merge to load Data Warehouse dimensions

    January 16th, 2012 in Blog, Business Intelligence, SQL Server

    In my last blog post I showed the basic concepts of using the T-SQL Merge statement, available in SQL Server 2008 onwards. In this post we’ll take it a step further and show how we can use it for loading data warehouse dimensions, and managing the SCD (slowly changing dimension) process. Before we start, let’s have a quick catch up on what an SCD is… What is a Slowly Changing Dimension (SCD)? If you want a full explanation of…

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  • Introduction to T-SQL Merge Basics

    December 13th, 2011 in Blog, SQL Server

    A number of Frog-Blog posts over the next couple of months are going to make heavy use of the awesome SQL Server MERGE statement, introduced in SQL Server 2008. I thought it best to write an introduction post to provide the basics and groundwork for future posts. So what does the Merge statement do? Merge upserts data into a table. If, like me, you find the word ‘upsert’ more than a little ridiculous, we can scrap it in favour of a slightly…

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