Emil Drkusic

Learn SQL: Foreign Key

January 7, 2020 by

In the previous article, we talked about the primary key (PK). In this one, we’ll check what is the foreign key (FK) and how it’s related to the primary key. This is the final step, after creating tables, inserting data, and defining primary keys, to cover all basics related to the database theory. There is much, much more than this, but if you understand these concepts, everything else is just expanding your knowledge around these basics.

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SQLShack

Best author award in 2019

January 3, 2020 by

2019 was a great year for the SQL Shack community, and 2020 is shaping up to be just as exciting. Thanks to our writers – SQL professionals and community members, we continue to spread the knowledge around the SQL community.

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Esat Erkec

An overview of the STRING_AGG function in SQL

January 3, 2020 by

In this article, we will explore the STRING_AGG function in SQL and we will also reinforce our learning with various examples. STRING_AGG function can be counted as a new member of the SQL aggregation functions and it was announced in SQL Server 2017. STRING_AGG function gathers all expression from rows and then puts it together in these rows expression in order to obtain a string. Additionally, this function takes a separator parameter that allows separating the expressions to be concatenated.

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Emil Drkusic

Learn SQL: Primary Key

December 20, 2019 by

If you’ve already worked with databases, then you could hardly miss the term – Primary Key (PK). And if you’re reading this series and use it to learn about databases, well, this article should give you a good overview of what the PK really is. Still, if you’re a database expert, maybe you’ll find something new or just refresh your knowledge. So, sit back, relax, and let’s dive into PKs.

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Jignesh Raiyani
Ranking Function Query with Result

Replace a SQL While loop and a cursor with ranking functions in SQL Server for better query performance

December 19, 2019 by

SQL While loop and cursor are the most common approach to repeat a statement on condition-based or determined limits. Loop and cursor can be utilized in a circumstance to deal with row-based processing in T-SQL. We generally observe moderate execution of old made procedures, which are composed of using loop and cursors. Those procedures take time, especially when the number of iteration count is big for the execution.

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Nisarg Upadhyay
Restrict Access must be Single_User

Send an alert when the database state changes to SQL Server single-user mode

December 18, 2019 by

This article explains the SQL Server single-user mode and how to configure an automated email alert when the state of the user database changes to the single-user mode. To send an alert, we will create a DDL trigger that executes when the user runs the ALTER DATABASE query. It collects the pieces of information using EVENTDATA() function, saves it in a temporary table, and sends an HTML formatted email.

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Dinesh Asanka
Data types for selected attributes in Time Series Model

Microsoft Time Series in SQL Server

December 12, 2019 by

The next topic in our Data Mining series is the popular algorithm, Time Series. Since business users want to forecast values for areas like production, sales, profit, etc., with a time parameter, Time Series has become an important data mining tool. It essentially allows analyzing the past behavior of a variable over time in order to predict its future behavior.

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Emil Drkusic

Learn SQL: INSERT INTO TABLE

December 12, 2019 by

In the previous article, we’ve created two tables, and now we’re ready to use the SQL INSERT INTO TABLE command and populate these tables with data. In order to do so, we’ll prepare statements in Excel and then paste these statements into SQL Server and execute them. We’ll also check the contents of both tables before and after these commands using the SELECT statement. So, let’s start.

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Nisarg Upadhyay
SQL Server version number in ERRORLOG file

Different methods to identify the SQL Server version number

December 11, 2019 by

In this article, I am going to show different methods to identify the SQL Server version number and its edition. Also, I have included the list of known SQL Server version numbers, Service Packs (SP), and Cumulative Updates (CU of MS SQL Server 2019, 2017). I have not included the hotfixes and CUs of SQL Server 2008 R2 and earlier versions.

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