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What is a Database Table?
A relational database is made up of several components, of which the table is most significant. The database table is where all the data in a database is stored, and without tables, there would not be...
View ArticleHow to Filter Query Results
In today’s lesson you’re going to learn how to filter query results using the WHERE clause. This clause is important as only those records matching the where clause’s conditions are returned in the...
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Database Indexes Explained
A database index allows a query to efficiently retrieve data from a database. Indexes are related to specific tables and consist of one or more keys. A table can have more than one index built from...
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Get Ready to Learn SQL Server: 4. Query Results Using Boolean Logic
In today’s lesson you’re going to learn more about filtering results returned from your queries using the WHERE clause using Boolean logic. The objectives of today’s lesson are to: Learn to use more...
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What is SQLite3?
SQLite3 Review SQLite3 is a compact free database you can use easily create and use a database. Though SQLite3 is not a full-featured database, it supports a surprisingly large set of the SQL...
View ArticleUse Pattern Matching in SQL to Filter Results
In this lesson you are going to explore how to use pattern matching in SQL with the LIKE operator. Using this phrase allows us perform partial matches of data values and obtain answers to questions...
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Ten Things a Junior DBA Should Learn
There is more to being a Junior DBA than knowing SQL. The DBA works at the intersection of the database, server, operations group, and developers. A DBA must understand concepts from all these facets...
View ArticleSQL GROUP BY – Use to Summarize Query Results
In today’s lesson you’re going to learn about grouping results returned from your queries using the SQL GROUP BY clause. The objectives of today’s lesson are to: Learn how to group results using GROUP...
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Keep is Simple: Easy To Understand Data Modeling Concepts
When working with SQL databases it is often useful to create diagrams of the database tables and their relationships. These may be done during the design process, as your data modeling, or once the...
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Database Normalization (Explained in Simple English)
Introduction to Database Normalization Database normalization is a process used to organize a database into tables and columns. The idea is that a table should be about a specific topic and that and...
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Learn about the First Normal Form and Database Design
This is the second in a series of posts teaching normalization. The first post introduced database normalization, its importance, and the types of issues it solves. In this article we’ll explore the...
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Database Second Normal Form Explained in Simple English
This is the third in a series of posts teaching normalization. The second post focused on the first normal form, its definition, and examples to hammer it home. Now it is time to take a look at the...
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Database Third Normal Form Explained in Simple English
This is the fourth in a series of posts teaching normalization. The third post focused on the second normal form, its definition, and examples to hammer it home. Once a table is in second normal form,...
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SQL Join – Introduction to Inner, Outer, and Cross Joins
SQL Joins are important to master. As you progress from a beginner to advance beginner, you’ll soon need to combine data from more than one table. To do this, you’ll use database joins. In this...
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Inner Join Introduction
An inner join is used when you need to match rows from two tables. Rows that match remain in the result, those that don’t are rejected. The match condition is commonly called the join condition. When...
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What is a Database NULL Value?
What is a Null Value? In databases a common issue is what value or placeholder do you use to represent a missing values. In SQL, this is solved with null. It is used to signify missing or unknown...
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Introduction to Outer Joins
Outer Joins Outer joins are used to match rows from two tables. Even if there is no match rows are included. Rows from one of the tables are always included, for the other, when there are no matches,...
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Learn to use Union, Intersect, and Except Clauses
Learn to use Union, Intersect, and Except Clauses The UNION, INTERSECT, and EXCEPT clauses are used to combine or exclude like rows from two or more tables. They are useful when you need to combine...
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Combine Table Rows Using UNION
Combine Table Rows Using UNION In this lesson we are going to talk about the UNION clause. You can use the UNION clause to combine table rows from two different queries into one result. Unlike a...
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What is the SQL INTERSECT Operator?
How to use the Intersect Operator The INTERSECT operator is used to combine like rows from two queries. It returns rows that are in common between both results. To use the INTERSECT operator, both...
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