Chapter 6. Querying

We have our data stored nicely in SimpleDB domains. Now we are going to learn the different ways to retrieve the stored data. Most of us are used to using Structured Query Language (SQL) for retrieving data from relational databases. SimpleDB uses a select syntax that is very similar to its counterpart in SQL for the queries. In this chapter, we will explore the query syntax provided by SimpleDB with a lot of samples and learn about:

• The basic select syntax

• Quoting values inside select expressions

• Predicates in select expressions

• Comparison operators

• Set operations

• Sorting

• Counting the results from SimpleDB queries

• Queries on multi-valued attributes

• GetAttributes