Year: 2020

Certification
SQL Server
Study

NOTES | Grouping and Windowing

SQL Server can perform some data analysis operations. A data analysis function is a function applied to a set of rows, and it returns a single value. An example of such a function is the SUM aggregate function. A data analysis function can be either a group function or a window function. The two types […]

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Certification
SQL Server
Study

NOTES | Combining Sets

Using Joins Often, data that you need to query is spread across multiple tables. The more normalized the environment is, the more tables you usually have. The tables are usually related through keys, such as a foreign key in one side and a primary key in the other. Then you can use joins to query […]

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Certification
SQL Server
Study

NOTES | Filtering and Sorting Data

While the traditional way to filter data in T-SQL is based on predicates, it also supports filtering data based on a specified number of rows and ordering. To do so, use TOP and OFFSET. Filtering Data with Predicates ON, WHERE, and HAVING are the three query clauses which enable your filtering of data based on […]

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Exam Preparation
Study
T-SQL

NOTES | Getting Started with the SELECT Statement

Using the FROM and SELECT Clauses The FROM and SELECT clauses are two principal clauses that appear in almost every query that retrieves data. When you execute a SELECT statement, it usually retrieves one or more rows of information – the exact number depends on how you construct the statement. These rows are collectively known […]

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Exam Preparation
SQL Server
Study

NOTES | Foundations of Querying

Foundations of Querying T-SQL is the main language used to manage and manipulate data in Microsoft’s main relational database management system (RDBMS), SQL Server—whether on premises or in the cloud (Microsoft Windows Azure SQL Database). It all stems from the mathematical principals of set theory and predicate logic. T-SQL is a dialect of standard SQL […]

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