1、truncate–删除所有数据,保留表结构,不能撤销还原 2、delete–是逐行删除速度极慢,不适合大量数据删除 3、drop–删除表,数据和表结构一起删除,快速 二、语法 truncate table 表名 delete from 表名 delete from 表名 where 列名=”value “ drop form 表名...
it deletes the entire records as well as the schema and structure of the table along with its named elements. The DROP command is a Data Definition Language (DDL) command. In addition, this command can also be used to drop databases. Databases or tables once dropped are wiped out of exis...
The below syntax is used to remove multiple databases from the SQL Server is as follows: DROP DATABASE Database_Name_1, Database_Name_2, Database_Name_3, Database_Name_N; Examples of DROP Database in SQL We will execute the SHOW DATABASES command to check which databases are residing i...
-A, –all-databases: 导出所有数据库。不过默认情况下是不会导出information_schema库。 -B, –databases: 导出指定的某个/或者某几个数据库,参数后面所有名字参量都被看作数据库名,包含CREATE DATABASE创建库的语句。 –tables: 导出指定表对象,参数格式为“库名 表名”,默认该参数将覆盖-B/–databases参数。
Once a database is dropped, you can check it in the list of databases with the following SQL command: SHOW DATABASES;Exercise? What is the purpose of the SQL DROP DATABASE statement? To delete a table from a database To delete all records in a table To delete an existing database To...
Drop Table Alter Database Alter Table Cancel Alter DML语句 Load 小批量导入 Cancel Load Export Delete SELECT语句 连接(Join) Order by Group by Having Limit Offset Union Distinct 子查询 with子句 SHOW语句 Show alter Show data Show databases Show load Show export Show partitions Show quota Show resou...
drop type AllDatabasesNameType go create type AllDatabasesNameType as table--自定义表类型用于存储数据库名称 ( rowNum int , name nvarchar(60), filename nvarchar(300) ) go IF EXISTS ( SELECT * FROM sysobjects WHERE id = OBJECT_ID(N'[BachBackupDataProc]') AND OBJECTPROPERTY(id, N'IsProcedu...
For example, to drop the database called my_db, the MySQL command would be: DROPDATABASEmy_db; This command removes the database and also removes the directory and files on the database server for the database. Just like the other databases here, there is no MySQL “delete database” ...
1.2 删:DROP, DROP DATABASE db1; drop database if exists db1; ##先查询,如果存在则删除。如果不存在,但是删除则会报错 1.3 查:SHOW, SHOW DATABASES ##返回的是所有数据库的名称。类似于 show tables show create database healthy ## 查看数据库的编码方式 #'healthy', 'CREATE DATABASE `healthy` ...
常用动词:create 创建表 drop 删除表6)CCL 指针控制语言 常用动词: declare cursor,feth into,update where current mysql数据库常见的管理命令 #语法create database database_name; (注意数据名不要以数字开头)#创建数据库zoomtechcreate database zoomtech;#查看所有数据库show databases;#查看某库的字符集show ...