mysql 查询不存在则插入

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• 摘要：CREATETABLE`test1`(`id`int(10)unsignedNOTNULLAUTO_INCREMENT,`item_no`varchar(10)NOTNULLDEFAULT'',`delete_flag`tinyint(3)unsignedNOTNULLDEFAULT'0',PRIMARYKEY(`id`))ENGINE=InnoDBAUTO_INCREMENT=5DEFAULTCHARSET=latin1insertintotest1(item_no,del

• 
  创建表: 

  CREATE TABLE `test1` ( 
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT, 
  `item_no` varchar(10) NOT NULL DEFAULT '', 
  `delete_flag` tinyint(3) unsigned NOT NULL DEFAULT '0', 
  PRIMARY KEY (`id`)
  ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1 

   

  ---

  不存在则添加，添加则忽略

• insert into test1 (item_no,delete_flag)
  select 'aaaaa',0 from dual
  where not exists (
      select `item_no`,`delete_flag` from test1 where item_no='aaaaa' and delete_flag=0
  );

例:

INSERT INTO `weixin_article_test`(artID, gzh_en, title, cover, summary, oriDate, content, ori_url, read_url) 
SELECT '203924112_1', 
'ynluxiren', 
'”泸西人“公众微信号正式开通啦', 'http://mmbiz.qpic.cn/mmbiz/JTA2OOtPMnjd2URJqg9niariaMHGzibZgruXqiaGYv7d8y95D15wwMlYOd41bcBqeRtb4N1uv2rKqKkSBGaGkcTqog/0', 
'力致于为全泸西人服务的微信公众号“泸西人”开通啦', 
'2015-03-02 21:27:53', 
'', 
'http://mp.weixin.qq.com/s?__biz=MzA3ODQwODM2NQ==&mid=203924112&idx=1&sn=13eb74e51bdd0669a2e06f93e8b768e8#rd', 
'' 
FROM dual 
WHERE NOT EXISTS (
  Select * from `weixin_article_test` where `gzh_en`='ynluxiren' AND `artID` = '203924112_1'
) 

//使用 dual 做表名可以让 select 语句后面直接跟上要insert字段的值，即使这些值还不存在当前表中.