1、判断表中如果没有则插入新纪录
INSERT INTO table(field1, field2, fieldn) SELECT 'field1', 'field2', 'fieldn' FROM DUAL WHERE NOT EXISTS(SELECT field FROM table WHERE field = ?)
INSERT INTO table(field1, field2, fieldn) SELECT 'field1', 'field2', 'fieldn' FROM DUAL WHERE NOT EXISTS(SELECT field FROM table WHERE field = ?)