--1. 删除表内所有记录--><deleteid="deleteALl">delete from table_name;</delete> 2. 根据主键删除记录 根据表的主键删除单条记录。 <!--2. 根据主键删除单条记录--><deleteid="deleteById"parameterType="java.lang.Integer">delete from table_name where id = #{id};</delete> 3. 根据多个条件删...
方法2:之前看到一个用truncate的方法,因为truncate效率高,只删除数据,跟delete类似,又有所不同.上面有说到两者的区别. mysql -uroot -pengine -h127.0.0.1 -e "select CONCAT('truncate TABLE ',table_schema,'.',table_name) from information_schema.TABLES where table_schema ='villadb'" > all.sql vim...
Summary: in this tutorial, you will learn how to use the PostgreSQL DELETE statement to delete data from a table. Introduction to PostgreSQL DELETE statement The PostgreSQL DELETE statement allows you to delete one or more rows from a table. The following shows the basic syntax of the DELETE ...
创建数据库: create database [数据库名]; 删除数据库: drop database [数据库名]; *重命名一个表: alter table [表名A] rename to [表名B]; *删除一个表: drop table [表名]; *在已有的表里添加字段: alter table [表名] add column [字段名] [类型]; *删除表中的字段: alter table [表名...
1). *创建数据库: create database [数据库名]; 2). *查看数据库列表: \d 3). *删除数据库: . drop database [数据库名]; 创建表: create table ([字段名1] [类型1] <references 关联表名(关联的字段名)>;,[字段名2] [类型2],...<,primary key (字段名m,字段名n,...)>;); *查看...
CREATE OR REPLACE FUNCTION count_em_all (limitNum INTEGER) RETURNS SETOF table_count AS ' DECLARE the_count RECORD; -- 当前行数 t_name RECORD; -- 当前表名 r table_count%ROWTYPE; BEGIN -- 循环所有表,对于每个表进行相关操作。 FOR t_name IN select concat_ws(''.'',''"''||pn.nsp...
/** * Delete all rows in the stocks table * @return int the number of rows deleted */ public function deleteAll() { $stmt = $this->pdo->prepare('DELETE FROM stocks'); $stmt->execute(); return $stmt->rowCount(); } Before running the methods, we query the data from the stocks ...
grant all on database 数据库名 to 用户名;#设置可操作的模式和权限 grant select,insert,update,deleteon all tablesinschemapublicto 用户名; 撤回权限 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #撤回在public模式下的权限 revoke select on all tablesinschemapublicfrom 用户名;#撤回在information_...
DELETE删除一个表中的行。DELETE FROM [ ONLY ] table [ WHERE condition ]DROP AGGREGATE删除一个用户定义的聚集函数。DROP AGGREGATE name ( type ) [ CASCADE | RESTRICT ]DROP CAST删除一个用户定义的类型转换。DROP CAST (source_type AS target_type) [ CASCADE | RESTRICT ]...
SELECT column1, column2,...columnN FROM table_name; 例: select * from postgtest ; 数据抽出选项 order by, limit(只取结果的前几条) , offset (只取从第几条到第几条) 例: select * from postgtest order by title desc limit 3 offset 4 ; 排序后从第4条开始取3条 统计抽出数据 ...