步骤4:批量插入数据 使用INSERT INTO … SELECT … FROM DUAL语句来实现批量插入数据,同时使用IF NOT EXISTS 来避免重复插入已存在的数据。 #批量插入数据sql = "INSERT INTO users (id, name) SELECT * FROM (SELECT %s, %s) AS tmp WHERE NOT EXISTS (SELECT id FROM users WHERE id = %s)" mycursor....
FROM suppliers WHERE not exists (select * from clients where clients.client_id = suppliers.supplier_id); 示例一:插入单条记录 复制代码代码如下: INSERT INTO clients (client_id, client_name, client_type) SELECT 10345, 'IBM', 'advertising' FROM dual WHERE not exists (select *fromclients where ...
Using INSERT ... ON DUPLICATE KEY UPDATE MySQL provides a number of useful statements when it is necessary toINSERTrowsafterdetermining whether that row is, in fact, new or already exists. Below we’ll examine the three different methods and explain the pros and cons of each in turn so yo...
INSERT INTO pay_namelist_temp ( `batchno`, `idserial`, `useranme`, `payproid`, `subpayproid`, `impdate`, `paystatus`, `payamt`, `status`, `orgcode`, `orderno`, `reservestr1`, `reservestr2`) VALUES ( '201712251109117', '108', '测8', '276', NULL, '2017-12-25 11:09...
This works well and is quite fast, more than checking if the row with an give id exists to update it or otherwise inserting it. When I explained the solution to the customer he said that this approach will cause the database in the hard disk grow indefinitely as we are inserting always...
上述代码中,首先使用INSERT INTO … SELECT …语句插入数据,并使用WHERE子句来进行判断,如果数据不存在则插入数据。然后使用ON DUPLICATE KEY UPDATE子句,在重复时执行更新操作,将重复数据的字段更新为新的值。 状态图 下面是一个使用状态图表示的示例,展示了"insert if not exists"的过程: ...
在MySQL中,可采用INSERT INTO ... ON DUPLICATE KEY UPDATE语句实现 insertOrUpdate 功能。 值得留意的是,在出现重复键时,会在先前索引值和当前值之间添加临时键锁,这可能导致死锁。 若要使用 INSERT INTO ... ON DUPLICATE KEY UPDATE 语句,需满足以下条件: ...
MySQL 当记录不存在时插入(insert if not exists) 示例一:插入多条记录 假设有一个主键为 client_id 的 clients 表,可以使用下面的语句: INSERTINTOclients (client_id,client_name,client_type) SELECTsupplier_id,supplier_name,'advertising' FROMsuppliers...
If the row is new, it will be added. Otherwise, the query will ignore the insert attempt and return this result: Query OK, 0 rows affected (0.00 sec) 2. UsingINSERT ... ON DUPLICATE KEY UPDATE Here is how the query looks like: ...
insert into student values (102,'张学友',1,508,17,'爱就像头饿狼~',0,0,0); 添加多名学生 INSERT INTO student(name,sex,class,age,description) VALUES ('周润发',1,508,17,'5个A~'),('周杰伦',1,508,17,'给我一首歌的时间~'); 注: 自动增长跟有默认值的字段可以不写。 更新数据(UPDATE...