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Tag Archives for " INNER JOIN "

Calculate a Running Total in SQL with Joins or Window Functions

There are several ways to calculate a running total in SQL.  In this article, we will cover two methods:  Joins, and Window Functions. We’ll first look at how to calculate the running total using an INNER JOIN.  By doing so, you’ll not only learn more about join conditions, but see how to take the result […]

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Joins versus Subqueries SQL Puzzle

Joins versus Subqueries

In this puzzle, we’re going to learn about joins versus subqueries.  In many queries you can substitute joins and subqueries.  Yet, since each has their strengths, it isn’t wise to do so.  Once you have worked through this puzzle you see some of the benefits and disadvantages of joins versus subqueries. Solving puzzles is a […]

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What is the difference between a subquery and inner join?

In this puzzle, we’re going to learn how to rewrite a subquery using inner joins.  Knowing about a subquery versus inner join can help you with interview questions and performance issues.  Though subqueries have unique abilities, there are times when it is better to use other SQL constructs such as joins. By reading this article […]

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Learn how to Work Joins and Messy Data

In this puzzle, we’re going to learn how to join dirty data using SQL Server.  Many times you’re forced to use someone else’s data.  Since it is their system and data, not yours, you can’t always fix the inconsistently formatted data before it is in the database. So how can you use it?  Do this […]

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What is the Difference Between Merge and Update?

When modifying one table based on the contents of another it may be tempting to simply use the merge statement, but before you throw away all other forms of modifying data, I think it’s important for you to know the difference between merge and update. What is the Difference Between MERGE and UPDATE? Both the […]

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Learn How to Combine Data with a CROSS JOIN

Cross Join Meme

A cross join is used when you wish to create combination of every row from two tables.  All row combinations are included in the result; this is commonly called cross product join.  A common use for a cross join is to create obtain all combinations of items, such as colors and sizes. Note:  The series […]

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Introduction to Common Table Expressions (CTE’s)

Common Table Expressions or CTE’s for short are used within SQL Server to simplify complex joins and subqueries, and to provide a means to query hierarchical data such as an organizational chart.  In this set of articles, we’ll introduce you to common table expressions, the two types, and their uses.  In this article we’ll introduce […]

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What is the Difference between Inner and Outer Joins?

Both inner and outer joins can be used to combine data from two or more tables; however, there are some key differences!  Read this article to find out each command’s strengths and when to use them. To get the most of this and our other lessons be sure to practice using the examples! All the […]

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Is it possible to use Joins, Subqueries, and Unions in one Query?

A reader recently asked me to help them solve a problem combining data from multiple tables into a single result.  What was interesting was that the solution used the three ways to combine data that we have recently covered, namely:  JOINS, set operators, and subqueries. Given the comprehensive nature of this problem I thought it […]

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Using Subqueries in the Select Statement

Subqueries in Select Statement

This is the second in a series of articles about subqueries.  In this article we discuss subqueries in the SELECT statement’s column list.  Other articles discuss their uses in other clauses. All the examples for this lesson are based on Microsoft SQL Server Management Studio and the AdventureWorks2012 database.  You can get started using these […]

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