insert_statement ::=
 INSERT_INTO {table_reference | [THE] (subquery1)}
 [(column_name [, column_name]...)]
 {VALUES (sql_expression [, sql_expression]...) 
 | subquery2} [RETURNING]
 [row_expression [, row_expression]... INTO 
 {variable_name | :host_variable_name} 
 [, {variable_name | :host_variable_name}]...];