1. 简单的SQL容易使用到MySQL的QUERY CACHE; 2. 减少锁表时间特别是使用MyISAM存储引擎的表; 3. 可以使用多核CPU。 truncate代替delete 当删除全表中记录时,使用delete语句的操作会被记录到undo块中,删除记录也记录binlog,当确认需要删除全表时,会产生很大量的binlog并占用大量的undo数据块,此时既没有很好的效率...
Exploring Advanced Applications of Union in SQL I’ve been delving into the world of SQL and I’m amazed at how powerful it can be when you start to explore its advanced features. One such feature is the UNION operator, which allows for combining data from two or more tables that share ...
下面选项中,关于SQL语句truncate table use的作用是解释,正确的是() A. 查询user表中的所有数据 B. 与“delete fom uset “完全一样 C. 删除user表,并再次创建user表
●RESTRICT:It is a default option in theTRUNCATE TABLEthat is used to decline truncation if any other tables have a foreign-key reference of tables. How to Use the TRUNCATE TABLE Statment From the psql? Open the SQL SHELL and perform the following steps to truncate a table from the selecte...
结果1 题目下面选项中,关于SQL语句truncate table user;的作用是解释,正确的是( ) A. 查询user表中的所有数据 B. 与“delete from user;“完全一样 C. 删除user表,并再次创建user表 D. 删除user表 相关知识点: 试题来源: 解析 D 反馈 收藏
truncate table table_name; set FOREIGN_KEY_CHECKS=1; (2) 使用delete from table_name 2.DRDS中不能进行全表扫描 解决方法: delete from table_name where 1=1; 3.主从复制导入数据时 防止生成binlog: set @@session.sql_log_bin=OFF;source *.sql ...
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TruncateTargetTableSwitchOption TryCastCall TryCatchStatement TryConvertCall TryParseCall TSEqualCall TSql100Parser TSql110Parser TSql120Parser TSql130Parser TSql140Parser TSql150Parser TSql160Parser TSql80Parser TSql90Parser TSqlAuditEventGroupHelper TSqlAuditEventTypeHelper TSqlBatch TSqlConc...
truncate:清空表,重新插入数据id从1开始;不占内存空间 delete table user; truncate table user; 删除delete表中的某条记录 delete from user where id=7; // 删除记录 insert into user (name,email,age,fee,password) values("lisi","9837194@qq.com", 36, 81.17, Password("lisi")); // id是从原来...
同时也就是我们在执行完grant create on schema to 用户;用户本身就可以具有在这个SCHEMA下拥有的所有的OBJECT 的处理权限,包含对表的insert, select, update ,delete truncate 等权利。 1 dbowner 可以认为是创建这个OBJECT的初创者,在没有复制权限的过程中,除了SUPERUSER 可以操作OBJECT ,dbowner 本身也可以操作他创...