SQL分页查询
thunder:
1.MYSQL实现
mysql> select * from user;
+----+----------+----------+-----------------+
| ID | username | password | email |
+----+----------+----------+-----------------+
| 1 | admin | admin | abc@yahoo.cn |
| 2 | thomas | 159753 | thomas@yahoo.cn |
| 3 | thomas1 | 159753 | thomas@yahoo.cn |
| 4 | huhu | 159753 | hu@yahoo.cn |
| 5 | fdg | dfg | fdg |
| 6 | sdf | sd | sdf@yahoo.cn |
| 7 | d | d | d@d.cn |
+----+----------+----------+-----------------+
7 rows in set (0.00 sec)
mysql> select * from user limit 3,2;
+----+----------+----------+-------------+
| ID | username | password | email |
+----+----------+----------+-------------+
| 4 | huhu | 159753 | hu@yahoo.cn |
| 5 | fdg | dfg | fdg |
+----+----------+----------+-------------+
2 rows in set (0.00 sec)
mysql>
===================================================
2.MSSQLServer实现
select top 5 function_id,function_name from d_function
where function_id not in (select top 5 function_id from d_function)
6 月统计
7 部门查询
8 公司查询
9 工程招标
10 工程总结
相关文档：
在取一个平均值的时候往往遇到小数点位数的截取。
前几天遇到过这么个问题，在KingDee EAS 的查询分析器里面如果求某一物料的平均单价时我这样写道：
select avg = case sum(bentry.FQuantity) when 0 then 0 else (sum(bentry.famount)/sum(bentry.FQuantity)) end,
此语句看似没什么问题，毕竟是求平均值，可是如果要� ......
方法一、尽量使用复杂的SQL来代替简单的一堆 SQL.
同样的事务，一个复杂的SQL完成的效率高于一堆简单SQL完成的效率。有多个查询时，要善于使用JOIN。
oRs=oConn.Execute("SELECT * from Books")
while not oRs.Eof
strSQL = "SELECT * from Authors WHERE AuthorID="&oRs("AuthorID") oRs2=oConn.Execute(strSQ ......
Table-Naming Standards
Table-naming standards, as well as any standard within a business, are critical to
maintaining control. After studying the tables and data in the previous sections, you
probably noticed that each table’s suffix is _TBL. This is a naming standard selected
for use, suc ......
低效: (索引失效)
SELECT … from DEPARTMENT WHERE DEPT_CODE IS NOT NULL;
高效: (索引有效)
SELECT … from DEPARTMENT WHERE DEPT_CODE >=0;
（27）总是使用索引的第一个列：
如果索引是建立在多 ......
