A query requests data from the database and receives the results. This process is also known as data retrieval. All SQL queries are expressed using the SELECT statement. You use the SELECT statement to retrieve all, or a subset of, the rows in one or more tables, and to retrieve all, or a subset of, the columns in one or more tables.

To learn more about SQL Anywhere query processing, including query optimization, selectivity estimation, and cost estimation, see the white paper "Query Processing Based on SQL Anywhere 12.0.1 Architecture" at  http://www.sybase.com/detail?id=1096047.