将对这四种数据库的操作封装到了2个类中可以拷贝过去直接使用. public sealed class OleDbClass { #region private utility methods & constructors //Since this class provides only static methods, make the default constructor private to prevent //instances from being created with "n
WITH RECURSIVE r AS (SELECT * FROM [表] WHERE id = xxxunion ALLSELECT [表].* FROM [表], r WHERE [表].id = r.parent_id)SELECT * FROM r ORDER BY id; 递归向上查询数据
查询出来的数据的编号,不是按照从1开始的有序进行的,界面上显示想显示有序排序 select RANK() OVER(ORDER BY id ) as ID ,* from reconcilet_detailes select RANK() OVER(ORDER BY 字段名 ) as ID ,ID from 数据库 如下图: 测试出,Postgre SQL ,SQL Server 好用
虽工作多年,但是sql的存储过程一致都没怎么用过,今天来按照博客https://www.cnblogs.com/applelife/p/11016674.html来学习一下(我使用postgre sql将这篇文章的例子都跑一遍). 新建一张students表: create table students( id int primary key, age int, name varchar(20), city varchar(20) ); insert into students values(1
Npgsql是PostgreSQL的一个.NET数据提供程序,它可以自由获取.它可以通过下列选项获得独立的下载,也可以安装PostgreSQL数据库程序时选择安装. 最新的_npgsql2 Npgsql2.0.13.91 已经修复一个重要bug:Replace Mono SslClientStream with .NET SslStream to fix SSL-related errors,而且还移除对Mono.Security的依赖. Npgsql2 has initial Entity F