1. 什么是 INSERT 语句? INSERT语句是SQL中的一种数据操作语言(DML)命令,用于向表中插入新记录。通过该命令,我们可以向MySQL表中添加单行或多行数据。单行插入十分简单,但多行插入在处理大量数据时会显得更为高效。 2. 基础语法 在MySQL中,插入数据的基本语法如下: INSERTINTO表名(列1,列2,列3,...)VALUES(...
1 row affected (0.00 sec) mysql> select * from dept_bak; +---+---+---+ | DEPTNO | DNAME | LOC | +---+---+---+ | 10 | abc | tj | | 10 | abc | tj | +---+---+---+ 2 rows in set (0.00 sec) mysql> rollback; Query OK, 0 rows affected (0.00 sec) mysql...
If an order has 10 items on it, I can select the item data which returns 10 rows of data (let's say 5 colums each). Beautiful! Now I find myself needing to satisfy a program that requires all of the data on a single row. I can do this in a higher level language, but if ...
//dev.mysql.com/doc/refman/5.0/en/example-auto-increment.html"Note For a multiple-row insert, LAST_INSERT_ID() and mysql_insert_id() actually return the AUTO_INCREMENT key from the first of the inserted rows. This allows multiple-row inserts to be reproduced correctly on other servers in...
Important: If you insert multiple rows using a singleINSERTstatement,LAST_INSERT_ID()returns the value generated for thefirstinserted rowonly. 使用单INSERT语句插入多条记录, LAST_INSERT_ID只返回插入的第一条记录产生的值. 比如 ID 2 是在插入第一条记录aaaa 时产生的.[当插入多条数据时。返回的id见...
Important: If you insert multiple rows using a singleINSERTstatement,LAST_INSERT_ID()returns the value generated for thefirstinserted rowonly. 使用单INSERT语句插入多条记录, LAST_INSERT_ID只返回插入的第一条记录产生的值. 比如 ID 2 是在插入第一条记录aaaa 时产生的.[当插入多条数据时。返回的id见...
...多行子查询(Multiple Rows Subquery)多行子查询返回多个值,通常用于与外部查询的某些列进行比较,使用 IN、ANY 或 ALL 等操作符。...子查询有多种形式:单行子查询、多行子查询、多列子查询、和 相关子查询。子查询通常用于 WHERE、FROM、SELECT 子句中。性能优化:有时候使用 JOIN 可以替代子查询,通常能提高...
打开sql\mysqld.cc文件的第 5239 行,将DBUG_ASSERT(0)改成DBUG_ASSERT(1),要不然调试时会触发断言; 现在我们可以编译整个工程了,选中 ALL_BUILD 项目,Build,然后静静的等待 5 到 10 分钟,如果出现了Build: 130 succeeded, 0 failed这样的提示,那么恭喜,你现在...
exclusive lock on the inserted row, but do not block each other because the rows are nonconflicting. If a duplicate-key error occurs, a shared lock on the duplicate index record is set. This use of a shared lock can result in deadlock should there be multiple sessions trying to insert ...
I am trying to insert a large number of rows into a mysql 5.5 database but it is very slow. Same code on POSTGRES and ORACLE is 100s times faster. For mysql I construct my INSERT statements as follows: INSERT INTO MY_TABLE VALUES ( 1, 1, 'text' ) , ( 2, 1, 'some text')...