6 SQL Query Management

You can use a query to retrieve data from one or more tables. A query is a statement that consists of zero or more variable declarations followed by single SELECT expression. The result of a query is always a sequence of records having the same record type.

Note: Subqueries are not supported in Oracle NoSQL Database.

Syntax

query ::= [variable_declaration] select_expression

For definitions of syntax components referenced in this statement, see:

• variable_declaration
• select_expression

Variable declarations and expressions will be defined later in this chapter. Before doing so, a few general concepts and related terminology must be established first.