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The Record That Never Existed (as a committed row)

Introduction According to the official documentation, the READ COMMITTED isolation level “specifies that statements cannot read data that has been modified but not committed by other transactions”. So, one could think that a record returned under this isolation level existed in the committed state at the time of reading. In this article, I am going […]

Implicit conversion from datetime to datetime2

A Solution for the Bin Packing Problem

A detailed description of a technique for the the solution of the Bin Packing Problem, that involves a recursive CTE and Window functions

A Plunge Into TOP

Introduction TOP is one of the many syntactical operators available in T-SQL and at a first view, it could seem very simple and not particularly interesting. According to the official documentation, it “limits the rows returned in a query result set to a specified number of rows or percentage of rows”. The following is the […]

Self SQL Injection

Based on a real fact, this article demonstrates how a bad use of sp_executesql can lead to unpleasant surprises

Work time calculation

One way to calculate how many minutes a person has worked considering holidays and shifts, being given starting and ending date / time

Indexing Foreign Keys

Foreign Keys are one of the fundamental characteristics of relational databases and enforce the referential integrity. Is it a good idea to index a FK relationship? When can it help?

Cardinality Estimator – What’s new in SQL Server 2014

SQL Server 2014 has introduced a rebuilt Cardinality Estimator (CE) with new algorithms. Which are the biggest differences between the new CE and the previous one? Which one works better? Read more to find out.