he SQL SELECT statement lets you query data from the database. In many of the previous chapters, you’ve seen examples of queries. Queries support several different types of subqueries, such as nested queries that run independently or correlated nested queries. Correlated nested queries run with a dependency on the outer or containing query.

This chapter shows you how to work with column returns from queries and how to join tables into multiple table result sets. Result sets are like tables because they’re two-dimensional data sets. The data sets can be a subset of one table or a set of values from two or more tables. The SELECT list determines what’s returned from a query into a result set. The SELECT list is the set of columns and expressions returned by a SELECT statement. The SELECT list defines the record structure of the result set, which is the result set’s first dimension. The number of rows returned from the query defines the elements of a record structure list, which is the result set’s second dimension.