用CASE WHEN实现sqlserver数据库的分类汇总功能
/*用CASE WHEN实现sqlserver数据库的分类汇总功能*/
/*例1：统计个数*/
/*表结构
id cityid major
1 1 A
2 1 B
3 2 B
4 2 A
5 1 A
6 2 B
7 1 C
8 2 C
结果：
cityId A B C
1 2 1 1
2 1 2 1
*/
SELECT cityId,SUM(CASE WHEN major='A' THEN 1 ELSE 0 END) AS 'A',
SUM(CASE WHEN major='B' THEN 1 ELSE 0 END) AS 'B',
SUM(CASE WHEN major='C' THEN 1 ELSE 0 END) AS 'C'
from TestCase1 GROUP BY cityId
/*例1：统计总和数*/
/*表结构
Id cityId catalogId Num
1 1 A 3
2 1 B 5
3 2 A 8
4 2 B 2
5 1 &
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//这是添加
private void button1_Click(object sender, EventArgs e)
{
string s = "Persist Security Info=False;Integrated Security=SSPI;database=IIntegration;server=(local)";
&n ......
MySQL:
SELECT column from table
ORDER BY RAND()
LIMIT 1
PostgreSQL:
SELECT column from table
ORDER BY RANDOM()
LIMIT 1
Microsoft SQL Server:
SELECT TOP 1 column from table
ORDER BY NEWID()
IBM DB2
SELECT column, RAND() as IDX
from table
ORDER BY IDX FETCH FIRST 1 ROWS ONLY
Thanks Ti ......
sqlserver2005有关键字ntile(x)和over(partition by.. order by..)子句配合.
比如获取每个表的前10%个字段。
select id , name , colid , rn from (
select * , rn = ntile (10 )
over (partition by id order by colorder )
from syscolumns )t where rn = 1 ......
E盘根目录新建一个Excel文件aa.xls后测试如下代码
use tempdb
go
if (object_id ('udf_getExcelTableNames' ) is not null )
drop function dbo .udf_getExcelTableNames
go
create function udf_getExcelTableNames (@filename varchar (1000 ))
returns @t table (id int , name varchar ( ......
在Google上使用“sql 分页”关键字进行搜索，几乎所有的答案都是那三条。其二效率最高，其三使用游标，效率最差。
下面是那三种方法 （插入代码没有sql选项）
方法1：
适用于 SQL Server 2000/2005
SELECT TOP 页大小 *
from table1
WHERE ......
