Complex SQL Queries Examples
Links to webpages containing advanced sql queries with examples
Complex SQL queries are best understood when learned with examples. Since SQL does not follow a sequential programming approach (SQL does not get executed line by line as that of C or PHP), learning the technology without viewing and understanding examples is not a good idea at all. Examples for SQL queries are as important as diagrams for high school biology lessons.
This lens makes an attempt to point to you some best resources where you can find good examples for advanced queries.
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Complex Group by Queries Examples
Many SQL programmers find Group By queries to be complex. However once get used to there is no other clause as useful as Group By. This clause is used for enhanced presentation of the output data by aggregating specified values across several rows. For example consider if a table used in a bank database contains customer ids along with dates and deposited amounts. In case if you want to view the net amount deposited by each customer you can use a Group By query grouped based on customer id.
SQL Joins Explained with Examples
SQL Joins work on data from more than one table. There are four kinds of Joins. Each one is quite different from the other.
Date Queries Explained With Examples
Storing, processing and retrieving date values on sql tables is often considered complex. Mastering date queries require a programmer to remember some important functions that process and present date in required formats. Moreover one has to be careful when using logical operators with dates. The tutorial by Tizag gives a fair idea to work with date queries.
SQL Expressions Explained With Examples
SQL Expressions are extra tasks taken care by databases that can reduce the overload on programming languages. The expressions can either be arithmetic or logical expressions. When used with conditional statements, the expressions become very powerful programming constructs.
SQL Views Query Examples
SQL views are predefined queries that can be used just like a table or other data structure. They can be compared with macros used in other programming languages. They don't do anything special other than help the programmers with lesser lines of code. Though they are complex to understand, once you get used to, they can in fact the reduce the complexity of sql queries that run into multiple lines. They make the queries to look simpler and neater. W3Schools has good online tutorial on SQL views
How To Learn Oracle SQL By Examples? - A Good Book Reviewed
'Oracle SQL By Example' is a book being used and appreciated by thousands of SQL professionals. There is no doubt that this book is the perfect handbook for those who would like to learn even the most complex of SQL queries by examples. This book is suitable for everyone right from beginners to professionals. The book does not only cover SQL programming but goes a step further in teaching you to write and execute the queries in the most widely used Oracle environment. In case you want to work on other databases such as MySQL or DB2, still the book can be of immense help. This is essentially due to the fact that SQL and its syntax is fairly similar across database management systems.
Overall, this is a perfect book to buy if you want to gain in depth SQL knowledge by practicing to the core.