T-SQL

Prashanth Jayaram

Overview of the SQL LIKE Operator

October 2, 2018 by

In this article, we are going to learn how to use the SQL LIKE operator, in SQL Server, using regular expressions to find and/or manipulate text. We will start by learning the symbols and basic syntax of using wildcard regular expressions. We will use character sets and repetition expressions to create flexible matching patterns, and along the way, we’ll examine different ways to use the LIKE operator. And then, finally, in the latter part of the section, we will explore some of the most common and most useful regular expression examples.

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Prashanth Jayaram

SQL Join overview and tutorial

September 17, 2018 by

The ability to combine results from related rows from multiple tables is an important part of relational database system design. In SQL Server, this is accomplished with the SQL join clause.  It’s the nature of traditional relational database systems where some table contains information related to other tables with a common key value. Using a SQL join, you can easily perform queries on related data-sets from multiple tables with these shared keys.

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Bojan Petrovic

Querying data using the SQL Case statement

September 12, 2018 by

The Case statement in SQL is mostly used in a case with equality expressions. The SQL Case statement is usually inside of a Select list to alter the output. What it does is evaluates a list of conditions and returns one of the multiple possible result expressions.

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Timothy Smith

Useful T-SQL techniques for development in SQL Server

July 17, 2018 by

When we’re developing solutions, we can sometimes forget useful commands we can use in T-SQL that make it convenient to remove data, eliminate objects, or carefully remove data. We look at three of these commands with a few examples of where we might consider using them in development, or in rare production cases. While they may offer us speed and convenience in some cases, we also look at some situations where they may not be the best tool to use.

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Timothy Smith

SQL Server – using lowest unit of measurement in T-SQL

July 2, 2018 by

A client recently discovered a discrepancy on one of our reports that showed an improvement in performance metrics but was inaccurate. Our reports came from a software tool, which showed the average performance throughout the day. It derived this number from periodic checks and the frequency changed, which affected our report. When we showed an improvement in the metrics on a report, the client showed us that the frequency change may have impacted this, not necessarily any improvement in performance. In situations where we’re measuring values and comparing them to other values, how can we prevent a change in measurement from impacting our reports? Read more »

Bojan Petrovic

How to implement error handling in SQL Server

June 15, 2018 by

Error handling overview

Error handling in SQL Server give us control over Transact-SQL code. For example when things go wrong we get a chance to do something about it and possibly make it right again. SQL Server error handling can be as simple as just logging that something happened or it could be us trying to fix an error. It can even be translating the error in SQL language because we all know how technical SQL Server error messages could get making no sense and hard to understand. Luckily we have a chance to translate those messages into something more meaningful to pass on to the users, developers, etc.

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Ben Richardson

Understanding SQL Server’s TRY_PARSE and TRY_CONVERT functions

May 16, 2018 by

Data conversion is one of the most fundamental tasks of any programming language. Data received from different sources is often not in the right format. For example, if you receive an XML file where age is in the string format and you want to calculate an average age for the people in the file you will need to convert age into an integer.

To make the conversion process simple, the TRY_PARSE and TRY_CONVERT functions were introduced in SQL Server 2012. Before TRY_PARSE and TRY_CONVERT, SQL Server only had the PARSE and CONVERT functions.

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Nikhilesh Patel

The HashBytes function in T-SQL

May 16, 2018 by

One of the paramount ways to guard data within a database is to utilize database encryption. However, no one encryption solution is perfect for all databases. Which encryption solution you select totally depends on the requirements of your application. Note that more powerful encryption for larger amounts of data requires a healthy amount of CPU. So, be prepared in the event that that introduction of encryption increases the system load.

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Ben Richardson

Sequence Objects in SQL Server

March 22, 2018 by

Sequence objects are used to sequentially generate numeric values. They were introduced in SQL Server 2012.

Sequence objects are similar to the IDENTITY column in any SQL table. However, unlike the IDENTITY column, they are independent and are not attached to any table. Sequence objects are used both independently and within the DML statements i.e. INSERT, UPDATE and DELETE.

This article will take a detailed look at sequence objects.

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SQLShack

SQL formatter tools

March 8, 2018 by

This collection of content will provide an overview of SQL formatter tools, with product page links for each of the tools. If you noticed a SQL formatter tool we missed, please let us know in the comments below.

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Daniel Calbimonte

How to upload multiple images to SQL Server

March 6, 2018 by

Introduction

Sometimes we need to store information including photos in our database. For example, the photo of the product, the photo of the team members. But how can we store images in SQL Server?

We could create an application in .NET or Java, but if we do not have experience in those programming languages, we could use SQL Server tools to do it.

In this new article, we will learn the following tips that will help us to work with images including how to:

  • insert one image into SQL Server
  • store multiple files into a table
  • verify that the images were inserted
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Ahmad Yaseen

SQL Server table hints – WITH (NOLOCK) best practices

February 14, 2018 by

SQL Server table hints are a special type of explicit command that are used to override the default behavior of the SQL Server query optimizer during the T-SQL query execution This is accomplished by enforcing a specific locking method, a specific index or query processing operation, such index seek or table scan, to be used by the SQL Server query optimizer to build the query execution plan. The table hints can be added to the FROM clause of the T-SQL query, affecting the table or the view that is referenced in the FROM clause only.

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Esat Erkec

How to use sargable expressions in T-SQL queries; performance advantages and examples

December 22, 2017 by

The challenge

One of the main tasks of a SQL Server database administrator is performance tuning. Sometimes, though, coders or developers don’t always prioritize database performance or query optimization. Here is a typical scenario

  • Imagine that developers create a new table and then insert some records in a test environment and test their queries to retrieve data from it
  • The query executed successfully and does not exhibit any symptoms of performance problems
  • The developer team release this table and query into production
  • One day you take a telephone from your colleague and he says my report is very slow
  • Bingo! In production, this table contains a lot of records and this is resulting in performance bottlenecks when querying it
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Ahmad Yaseen

What to choose when assigning values to SQL Server variables: SET vs SELECT T-SQL statements

November 29, 2017 by

SQL Server provides us with two methods in T-SQL to assign a value to a previously created local variable. The first method is the SET statement, the ANSI standard statement that is commonly used for variable value assignment. The second statement is the SELECT statement. In addition to its main usage to form the logic that is used to retrieve data from a database table or multiple tables in SQL Server, the SELECT statement can be used also to assign a value to a previously created local variable directly or from a variable, view or table.

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Sifiso W. Ndlovu

ETL optimization using SQL Server TRY Functions

October 24, 2017 by

Introduction

An enterprise data warehouse ETL solution typically includes, amongst other steps, a data transformation step that converts source data from one data type into another. It is during this step that type conversion errors may occur and depending on the type of exception handling techniques implemented in the ETL solution (or lack thereof), frustration may occur for both ETL developers and DBAs when trying to identify and resolve type conversion errors. In this article we take a look at a trio of SQL Server built-in functions that were introduced in SQL Server 2012, namely, TRY_PARSE, TRY_CAST, and TRY_CONVERT and how they could be utilized to reduce type conversion errors in ETL solutions and thereby saving developers needless troubleshooting exercise.

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Prashanth Jayaram

Monitoring SQL Server database status changes using T-SQL and PowerShell scripts

October 17, 2017 by

Monitoring a SQL Server database is a critical component of database administration. Ninety percent of the organizations expect the number of databases to increase over the next twelve months. An increase in data volumes can have negative effects on the availability of databases. Hence, SQL Server database monitoring is considered a critical responsibility of a database administrator. Organizations tend to spend a lot of their funds towards enterprise solutions. And due to the sensitive and growing nature of business and user needs, application availability is very important nowadays.

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