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Free ebooks
 Free database ebooks SQL Beginning SQL Queries: From Novice to Professional
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 Chapter 1 Relational Database Overview - In this chapter, we will look at some of the basic ideas of data models and relational theory so we can get started on formulating queries in SQL.Chapter 2 Simple Queries on One Table - In this chapter, we will look at choosing values from just one table.The table may be one of the permanent tables in our database, or it may be a virtual table that has been temporarily put together as part of a more complicated query. Chapter 3 A First Look at Joins - The join is one of the relational algebra operations, so we will first look at the definition in terms of the algebra. The algebra tells us how to get the result we are looking for, and a join has two steps. The first step involves an operation called a Cartesian product. Chapter 4 Nested Queries - In this chapter, we will look at nested queries and two new SQL keywords, EXISTS and IN. We will see how to use nesting to perform some of the queries we have already done and also how this will open up some other possibilities. Chapter 5 Self Joins - In this chapter, we’ll explore more complex queries on a single table—in particular, those requiring us to look at more than one row of the table at a time. Chapter 6 More Than One Relationship Between Tables Chapter 7 Set Operations - The algebra notation introduced in Chapters 1 and 2 is a useful way of expressing queries, especially as they become more complex. I will use the algebra notation in this chapter, but will always give you an SQL equivalent so you can choose which representation you find the most helpful. Chapter 8 Aggregate Operations - In this chapter, we will look at some of the functions for summarizing data—for example, to count all the senior members in the club—and how to make the best use of them. Chapter 9 Efficiency Considerations - In this chapter, we will take a brief look at what goes on when a query is performed, how to determine if the phrasing of the query matters, and how indexes might help with the efficiency of some queries. Chapter 10 How to Approach a Query - Usually, it is just a matter of being confident and relaxing. Large, complicated queries can always be broken down into a series of smaller, simpler queries that can be combined later. Chapter 11 Common Problems - In this chapter, we will look at some common design and data problems, and also some of the most common syntactic mistakes. Download ebooks on sql:Beginning SQL Queries: From Novice to Professional
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