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SQL Challenge #10 – when Database Settings impact performance

SQL Challenge #10 – when Database Settings impact performance

by Uwe Ricken | Nov 3, 2025 | Level 200, SQL Challenges

Problem Description / Requirement A customer is reporting a deterioration in the performance of all queries after the software vendor updated the database objects using a T-SQL script. After the vendor completed the updates, the customer discovered that the query row...
SQL Challenge #10 – when Database Settings impact performance

SQL Challenge #9 – When Estimates are wrong

by Uwe Ricken | Oct 22, 2025 | Level 200, SQL Challenges

Problem Description / Requirement This example comes from a software application that has strictly implemented its relational model. The challenge uses two tables linked by referential integrity. The [dbo].[marketsegments] table serves as a reference table for the...
SQL Challenge #8 – Overlapping Time Series

SQL Challenge #8 – Overlapping Time Series

by Uwe Ricken | Jul 7, 2025 | Level 400, SQL Challenges

Problem Description / Requirement This example comes from a customer from the automtive sector. Whenever a vehicle is built, EVERY single step must be precisely recorded. So-called “telegrams” are used for this purpose. These telegrams can convey simple...
SQL Challenge #7 – Dynamically added attributes

SQL Challenge #7 – Dynamically added attributes

by Uwe Ricken | Apr 7, 2025 | Level 300, SQL Challenges

Problem Description / Requirement This – simplified – problem arises from software that allows for individual customization to meet customer needs. A customer uses the software as a grading system for students at their university. A separate column has been...
SQL Challenge #8 – Overlapping Time Series

SQL Challenge #6 – Locking locks your SQL Server

by Uwe Ricken | Mar 3, 2025 | Level 400, SQL Challenges

Problem Description / Requirement Your customer is using new software in the company. This software uses its own logic for protocol measures and locks because – presumably – the concept of intelligent locking is not known. Before each query is called, the...
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SQL Challenges

  • SQL Challenge #10 – when Database Settings impact performance 2025-11-03
  • SQL Challenge #9 – When Estimates are wrong 2025-10-22
  • SQL Challenge #8 – Overlapping Time Series 2025-07-07
  • SQL Challenge #7 – Dynamically added attributes 2025-04-07
  • SQL Challenge #6 – Locking locks your SQL Server 2025-03-03
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