Home | 简体中文 | 繁体中文 | 杂文 | 打赏(Donations) | ITEYE 博客 | OSChina 博客 | Facebook | Linkedin | 知乎专栏 | Search | About

第 5 章 DML (Data Manipulation Language)

目录

5.1. INSERT
5.1.1. INSERT INTO ... SELECT
5.1.2. INSERT IGNORE
5.1.3. INSERT...ON DUPLICATE KEY UPDATE
5.2. REPLACE
5.3. DELETE
5.3.1. 删除重复数据
SELECT - retrieve data from the a database
INSERT - insert data into a table
UPDATE - updates existing data within a table
DELETE - deletes all records from a table, the space for the records remain
CALL - call a PL/SQL or Java subprogram
EXPLAIN PLAN - explain access path to data
LOCK TABLE - control concurrency
	

5.1. INSERT

5.1.1. INSERT INTO ... SELECT

SET @OLDTMP_SQL_MODE=@@SQL_MODE, SQL_MODE='';
DELIMITER //
CREATE TRIGGER `members_mobile_insert` BEFORE INSERT ON `members_mobile` FOR EACH ROW BEGIN
	insert into members_location(id,province,city) select NEW.id,mobile_location.province,mobile_location.city from  mobile_location where mobile_location.id = md5(LEFT(NEW.number, 7));
END//
DELIMITER ;
SET SQL_MODE=@OLDTMP_SQL_MODE;
			

5.1.2. INSERT IGNORE

INSERT IGNORE 与INSERT INTO的区别就是INSERT IGNORE会忽略数据库中已经存在 的数据,如果数据库没有数据,就插入新的数据,如果有数据的话就跳过这条数据。

insert ignore into table(name)  select  name from table2
			

5.1.3. INSERT...ON DUPLICATE KEY UPDATE

			
create table foo (id serial primary key, u int, unique key (u));

insert into foo (u) values (10);
insert into foo (u) values (10) on duplicate key update u = 20;

mysql> select * from foo;
+----+------+
| id | u    |
+----+------+
|  1 |   20 |
+----+------+