A Funny Substring NULL

Handling an unknown number of parameters in SQL Server

In this article we compare performance differences when splitting comma separated strings using TVPs, TVFs, openjson, string_split and more.

Operator Precedence

A Simple Error

Model and Log Trend Reversals for Time Series Data in SQL Server

This tip demonstrates models for detecting the start of periods of rising or falling financial securities prices based on exponential moving averages. The demonstration is simplified because it relies on a log to keep track of time series values as well as exponential moving averages with different period lengths.

Concatenating Dynamic SQL

Learning the SQL GROUP BY Clause

Learn about the various ways to use the GROUP BY command to summarize and rollup query results. We look at the basics with examples as well as using group by rollup, cube and grouping sets.

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

How LAG compares to other techniques

LAG pulls a column from another row without a self-join. In this article, Kathi Kellenberger shows how LAG compares to other techniques