p*i
发帖数: 15 | 1 【 以下文字转载自 Software 讨论区,原文如下 】
发信人: pci (futureio), 信区: Software
标 题: Coldfusion 怎样实现嵌套查询?
发信站: The unknown SPACE (Wed Jun 19 15:50:26 2002) WWW-POST
Wish to implement a web form generator, met the following problem:
...
But Coldfusion reports error saying that it cannot do nested query, it
suggested using grouping,
Because I wish to implement query2 as a subquery, and the results returne |
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G***G
发帖数: 16778 | 2 a web page using php. the web page has four tabs. each tab includes one
table from one query. there are tab1, tab2, tab3, tab4, and query1, query2,
query3, query4.
open database
query1
query2
query3
query4
should I put fetch_array here?
should I put close database here for each query?
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f*****e
发帖数: 5177 | 3 I run SQL query estimated execution plan again one query.
The plan showed that the cost of "delete" and "insert" is 900%.
What does that mean?
PS: Which one of the following queries is better?
Query1:
if exist (select * from table1 where ...)
begin
update table1 set ...
end
else
begin
insert into table1 ...
end
Query2:
if exist (select * from table1 where ...)
begin
delete from table1 where ...
end
insert into table1 ...
Query3:
delete from table1 where ...
insert into table1 ... |
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g***l
发帖数: 18555 | 4 保险起见Access里写两个QUERY吧
QUERY1: SELECT FIELD3, MAX(FIELD2) AS MAXFIELD2 FROM TABLE GROUP BY FIELD3
QUERY2: T.* FROM QUERY1 Q1, TABLE T WHERE FIELD1=1
AND Q1.MAXFIELD2=T1.FIELD2 AND Q1.FIELD3=T.FIELD3 |
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S**H
发帖数: 1256 | 5 query1:
ID NOT=( sub query)
query2:
ID NOT IN (sub query)
两个subquery 都是一样的. 为什么query1 返回的值没有完全过滤掉subquery的ID.
NOT= , NOT IN 有啥区别?
谢谢!!! |
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g*****g
发帖数: 34805 | 6 For non-trivial application, you should use a connection pool to
maintain database connections. I bet there's php framework
for that.
query2, |
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c******5
发帖数: 22 | 7 The name of the excel sheet is 'Query2'(you could check from the log message
Do you have any suggestions? |
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c******5
发帖数: 22 | 8
columns.
的确是有mixed的数据。可是我转了个相似的data没问题啊。详细说说吧：
1. 我在access里要用到它的3个tables中的信息。首先，我一个table一个table的把它
们变成了excel file，然后用proc import一个一个的把它们转到SAS中。成功。
2. 因为我想把3个tables中的信息放在一个table中在SAS中做Analysis，但SAS中用
merge什么我怕有multiple entries （不同的table有不同数量的multiple entries）
容易出错。所以我在access里用query把这三个tables先放到一起，然后转成一个excel
sheet，最后录入SAS。 于是就给出了error message。
所以我觉得mixed的数据类型应该不是问题，因为之前没有出错啊。我能想到的就是
combine了以后row 太多，但前面也有朋友说SAS能handle很大的数据，应该也不是问题
。还有就是SAS能发现我这个新的excelsheet是从access中combine了不同的tables来的
所以有问题？ 觉得这... 阅读全帖 |
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