The Toolbar page of the Options window in Interactive SQL has these components:
Execute all statements Executes all text in the SQL Statements pane. This is the default. You can also perform this operation by pressing F5 or clicking Execute all SQL statement(s).
Execute selected statements Executes the text that is selected in the SQL Statements pane. If no text is selected, all the statements are executed. You can also perform this operation by pressing F9 or choosing SQL | Execute Selection.