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Oracle取前N条记录方法 Oracle实现SELECT TOP N的方法 - 数据库(内核) - 清...
...from tablexxx order by xxx desc ) where rownum <= Noracle数据库不支持mysql中limit, top功...select * from ( select * from tablexxx order by xxx desc ) where rownum <= N
oracle数据库不支持mysql中limit, top功能,但可以通过rownum来限制返回的结果集的行数,rownum并不...
Postfix日常维护队列管理 - 更多技术 - 清泛网 - 专注C/C++及内核技术
.../local/httpd/logs/error_log tail -f /usr/local/httpd/logs/suexec_log
mysql相关：tail -f /usr/local/mysql/data/linux.linux.com.err
测试amavisd：amavisd -d config debug-sa
测试spam：spamassassin -D --lint
测试maildrop：maildrop -V 10 -dtest@test.com
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PHP的函数前加上“@”的作用 - PHP - 清泛IT论坛，有思想、有深度
@是PHP提供的错误信息屏蔽的专用符号。
比如在一个函数前使用@
@mysql_query 不会出现Warning，
而原来mysql_query 在遇到错误时会在页面上访提示Warning。
IN vs OR in the SQL WHERE Clause
...')
WHERE foo = 'a' OR foo = 'b' OR foo = 'c'
According to the manual for MySQL if the values are constant IN sorts the list and then uses a binary search. I would imagine that OR evaluates them one by one in no particular order. So IN is faster in some circumstances.
The best way to know is to p...
Add a prefix to all Flask routes
... container (anything that speaks WSGI will do) and to set your APPLICATION_ROOT config value to your prefix:
app.config["APPLICATION_ROOT"] = "/abc/123"
@app.route("/")
def index():
return "The URL for this page is {}".format(url_for("index"))
# Will return "The URL for this page is /abc/123/...
How to implement a tree data-structure in Java? [closed]
...
Here:
public class Tree<T> {
private Node<T> root;
public Tree(T rootData) {
root = new Node<T>();
root.data = rootData;
root.children = new ArrayList<Node<T>>();
}
public static class Node<T> {
priva...
My Git repository is in the wrong root directory. Can I move it? (../ instead of ./)
...or so ago I ran the command in the directory one directory higher than the root of my project.
9 Answers
...
How do I list all cron jobs for all users?
...
You would have to run this as root, but:
for user in $(cut -f1 -d: /etc/passwd); do crontab -u $user -l; done
will loop over each user name listing out their crontab. The crontabs are owned by the respective users so you won't be able to see another u...
SQL Server: SELECT only the rows with MAX(DATE)
...
For MySql you can do something like the following:
select OrderNO, PartCode, Quantity from table a
join (select ID, MAX(DateEntered) from table group by OrderNO) b on a.ID = b.ID
...
How to generate a range of numbers between two numbers?
...0
DECLARE @endnum INT=1050
;
WITH gen AS (
SELECT @startnum AS num
UNION ALL
SELECT num+1 FROM gen WHERE num+1<=@endnum
)
SELECT * FROM gen
option (maxrecursion 10000)
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