sql 备忘
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**** sql 查询备忘 ****
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一:外连接:
1、左外连接(把join左边表里的所有数据都查出来。然后把join 右边表中的符合条件的数据加在左边表的后面。。。。)
SELECT * from t_empl_info as a LEFT OUTER JOIN t_dept as b
ON a.dept_no=b.dept_id
--通常情况下是:左边表是多方表。右边表是一方表
--三张表的左外连接
SELECT *
from A left join B
on A.a=B.a
left join C on B.b = C.b;
相关文档:
1. Q. What is a join?
A. Join is a process of retrieve pieces of data from different sets (tables) and returns them to the user or program as one joined collection of data.
2. Q. Can a table have more than one foreign key defined?
A. A table can have any number of foreig ......
你的SQL Server 2000必须打上SP3的补,然后安装Microsoft的JDBC驱动,将以下三个jar包复制到WebContent\WEB-INF\lib
msbase.jar
mssqlserver.jar
msutil.jar
下面是测试代码,没有报错数据库就能正常连接
public class DbcTest {
/**
* @param args
*/
public static void main(String[] args) {
Str ......
写一个存储过程,将表一按照表二的形式进行查询。
仓库名称 商品名称 数量
A
S001 12
A S002 17
A
S003 10
B S001 21
B
S002 5
B S003 ......
很多时候我们可能都需要这么一个简繁互相转换的SQL函数,今天在网上找到的,收集下来。
以后有了它就省事多啦。不用再写程序取出来转换后再更新数据库了。
SQL简体繁体转换函数代码:
--生成码表
if exists (select * from dbo.sysobjects where id = object_id(N'[codetable]') and OBJECTPROPERTY(id, N'IsUserTable' ......
protected void Button1_Click(object sender, EventArgs e)
{
string strsql = "select * from TreeViewTemp where parentID=0";
DataTable dt = db.GetDataTable(strsql);
StringWriter sw = new StringWriter();
//StreamWriter sw = new Strea ......