SQL Server 2008 Spatial, PostgreSQL/PostGIS 1.3
General Overview
FeatureSQL Server 2008 (RC0)MySQL 5.1/6PostgreSQL 8.3/PostGIS 1.3/1.4
OS
Windows XP, Windows Vista, Windows 2003, Windows 2008
Windows XP, Windows Vista, (haven't tested on 2008), Linux, Unix, Mac
Windows 2000+ (including Vista and 2003, haven't tested on 2008), Linux, Unix, Mac
Licensing
Commercial - Closed Source, Various levels of features based on version, Express version has full spatial support but limitation on database size and only use one processor.
Commercial Open Source (COSS), some parts GPL. Here is an interesting blog entry on the subject MySQL free software but not Open Source. The comments are actually much more informative than the article itself.
FLOSS (PostgreSQL is BSD, PostGIS is GPL Open Source - you can use for commercial apps but if you make changes to the core libraries of PostGIS, you need to give that back to the community)
Free GIS Data Loaders
shp dataloader for SQL Server 2008 developed by Morten Nielsen (doesn't yet work with RC0)
OGR2OGR, shp2mysql.pl script
included shp2pgsql, OGR2OGR, QuantumGIS SPIT, SHP loader for PostGIS also developed by Morten using SharpMap.NET various others
Commercial GIS Data Loaders
Manifold, Safe FME Objects, ESRI ArcGIS 9.3 (in a later service pack)
Safe FME Objects
Manifold, FME Objects, ESRI ArcGIS 9.3
Application drivers available specifically for spatial component
? Not yet - SharpMap.NET eventually and probably built into new ADO.NET 3.5+
GDAL C++, SharpMap via OGR, AutoCAD FDO
SharpMap.Net, JDBC postgis.jar included with postgis, JTS etc. tons for Java, GDAL C++, AutoCad FDO beta support
Free Object/Relational Mapping
NHibernateSpatial (this is a .NET object relational spatial mapper) - beta support
Hibernate Spatial - this is a java object relational mapper
NHibernateSpatial and HibernateSpatial
Free Desktop Viewers and Editors
Will be built into SQL Manager, but not available in RC0 and only useful for viewing
GvSig
OpenJump, QuantumGIS, GvSig, uDig
相关文档：
update CHELIANG_MINGDAN set clmd_yunxuzaizhong = cast(clmd_yunxuzaizhong/1000 as decimal(14,4)) where clmd_yunxuzaizhong is not null
update CHELIANG_MINGDAN set clmd_carweight = cast(clmd_carweight/1000 as decimal(14,4)) where clmd_carweight is not null ......
SQL 中的 substring 函数是用来抓出一个栏位资料中的其中一部分。这个函数的名称在不同的资料库中不完全一样：
MySQL: SUBSTR(), SUBSTRING()
Oracle: SUBSTR()
SQL Server: SUBSTRING()
最常用到的方式如下 (在这里我们用SUBSTR()为例)：
SUBSTR(str,pos): 由<str>中，选出所有从第<pos>位置开始 ......
做个矩阵，其实就是个二维数组，关键是要从数据库里调些数据，sql语句不熟练，就边学边用，同步地记些笔记，方便查阅
关于distinct和order by 发了个帖子（第一次哦）
首帖：
用的是oracle的数据库
目的是想选出唯一的userid（原有重复值）,并且按照filepos排序（原filepos是1，2，3.。。不重复的序号）
......
我们使用oracle的人都知道可以通过rownum伪列得到查询结果序列前面的指定的行，为了下面更好的进行说明问题，我们先来创建一个数据表table1：
create table table1
(AAA integer primary key,
BBB varchar(30));
然后在table1中插入9条数据：
insert into table1 values (8, 'good');
insert into table1 values (7 ......
今天终于把这个问题给解决了：
参考文章：http://blog.csdn.net/long2006sky/archive/2007/04/23/1576583.aspx
实例说明：
环境：win2k+sqlserver 2K+查询分析器
SQLSERVER服务实例 ......
