This article is about basics of conventional SQL unit testing concepts and its implementation through tSQLt, a highly acclaimed SQL unit testing framework because of being written in T-SQL and its built-in design support for SQL SQL unit testing needs ranging from simple to complex scenarios.
Since we know that the SQL CTE (common table expression) offers us a tool to group and order data in SQL Server, we will see an applied example of using common table expressions to solve the business challenge of re-basing identifier columns. We can think of the business problem like the following: we have a table of foods that we sell with a unique identifier integer associated with the food. As we sell new foods, we insert the food in our list. After a few years, we observe that many of our queries involve the foods grouped alphabetically. However, our food list is just a list of foods that we add to as needed without any grouping. Rather than re-group or re-order through queries using a SQL CTE or subquery, we want to permanently update the identifier.Read more »
In this article, we will discuss and learn basics and all details about SQL Server data type converting operations and also we will review the SQL CONVERT and TRY_CONVERT built-in functions with various samples. At first, we will explain and clarify syntax of the SQL CONVERT function and then we will learn how can we make data converting process numerical and date/time data types to character data.Read more »
In this article, the latest in our series on Common table expressions, we’ll review CTE SQL Deletes including analyzing the operation before the delete, actually removing the data as well as organizing and ordering the deletes with CTEs.Read more »
In CTEs in SQL Server; Querying Common Table Expressions the first article of this series, we looked at creating common table expressions for select statements to help us organize data. This can be useful in aggregates, partition-based selections from within data, or for calculations where ordering data within groups can help us. We also saw that we weren’t required to explicitly create a table an insert data, but we did have to ensure that we had names for each of the columns along with the names being unique. Now, we’ll use our select statements for inserts and updates.Read more »
Common table expressions (CTEs) in SQL Server provide us with a tool that allows us to design and organize queries in ways that may allow faster development, troubleshooting, and improve performance. In the first part of this series, we’ll look at querying against these with a practice data set. From examples of wrapped query checks to organization of data to multiple structured queries, we’ll see how many options we have with this tool and where it may be useful when we query data.Read more »
This article will provide an overview of SQL Server implicit conversion including data type precedence and conversion tables, implicit conversion examples and means to detect occurrences of implicit conversionRead more »
From troubleshooting many data flow applications designed by others, I’ve seen a common pattern of over complexity with many designs. Putting aside possible risks by introducing too much complexity, troubleshooting these designs often involves opening many different applications – from a notepad file, to SSIS, to SQL Server Management Studio, to a script tool, etc. It may sound like many of these are doing a hundred steps, yet many times, they’re simply importing data from a file, or calling five stored procedures and then a file task of moving a file. This complexity is often unnecessary, as is opening many different tools when we can use a few tools and solve issues faster.Read more »
CRUD operations are foundation operations every database developer and administrator needs to understand. Let’s take a look at how they work with this guide.Read more »
This article will cover the STRING_SPLIT function in SQL Server including an overview and detailed usage examples.
One calculation that you are almost guaranteed to have to produce in your career as a T-SQL developer relates to the calculation of a turnaround time. This is often a key KPI for measuring the performance of both individuals and teams, particularly when the business operates within a service-oriented sector i.e. customer support, transportation, healthcare etc. Turnaround time calculation does not only refer to business metrics rather any activity (i.e. ordering a pizza) with a recorded start and an end time can have its own turnaround time calculated. In this article we evaluate different options for calculating a turnaround time including using DATEDIFF function, creating your own user-defined function (UDF) as well as an integration with SQL Server Master Data Services.Read more »
In this article, I’ll show you how to find and replace data within strings. I will demonstrate how to use the function SQL REPLACE, where you look for a substring within a string, and then replace it.
A SQL index is used to retrieve data from a database very fast. Indexing a table or view is, without a doubt, one of the best ways to improve the performance of queries and applications.
A SQL index is a quick lookup table for finding records users need to search frequently. An index is small, fast, and optimized for quick lookups. It is very useful for connecting the relational tables and searching large tables.Read more »
In this article, we’ll walk-though two other important SQL aggregate function, SQL COUNT and COUNT_BIG. In the previous article of this series, we covered how to retrieve data, join tables, work with dates and times, use window functions, filter data, and much more.Read more »
In this article, we’ll walk-through the concept of the SQL Order by clause and understand how the SQL engine works with the ordering result in a query.Read more »
A SQL Join clause is put within a Select statement and at the end, it’s given a join condition, which tells the database how to fetch your data. The column specified within the join condition must be preceded by a table name if the column name is the same in both tables. When a column is preceded with a table name, it’s known as a qualified column.Read more »
The SQL Like is a logical operator that is used to determine whether a specific character string matches a specified pattern. It is commonly used in a Where clause to search for a specified pattern in a column.Read more »
In this article, we’re going to discuss the SQL ROW_NUMBER function. This is a continuation of the SQL essential series. In this guide, I’ll explain what a window function is all about, and you’ll see sample examples to understand the concepts behind the SQL ROW_NUMBER function.Read more »
SQL date format functions like the DateDiff SQL function and DateAdd SQL Function are oft used by DBAs but many of us never took the time to fully understand these extremely useful features. For professionals just getting started with SQL Server, these functions are some of the first to become familiar with. So hopefully this article will have a little something for everyone across the skill spectrumRead more »
In this article, we’ll take a look into SQL truncate improvement in SQL Server 2019.
Data inserts and updates are a normal and regular task for the developers and database administrators as well as from the application. The source of the data can be in multiple forms as if direct insert using T-SQL, stored procedures, functions, data import from flat files, SSIS packages etc.Read more »
This article on the SQL Delete is a part of the SQL essential series on key statements, functions and operations in SQL Server.Read more »
This article will provide a review of SQL code formatting using the SQL formatter options in SSMS
Nobody likes to read a large amount of text, even when it’s just a plain one. When reading SQL script where there is a large amount of non-formatted SQL code, the problem becomes even bigger.Read more »
The SQL Join clause is one of the major components of the Select statement, which is used to pull data out of SQL Server
The Select keyword starts the statement. It’s often followed by a star (*) AKA splat as some DBAs call it.Read more »