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What does $$ mean in the shell?
...e mktemp option -t is now deprecated (I think because of problems with the char -). Use mktemp ${tempfoo}.XXXXXX these days. I take the liberty to update your post.
– Sebastian
Jan 10 '14 at 11:44
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PostgreSQL - fetch the row which has the Max value for a column
...sted index lookup into lives - on my machine
-- the latter query plan was selected given my memory settings and
-- histogram
SELECT
l1.*
FROM
lives AS l1
INNER JOIN (
SELECT
usr_id,
MAX(time_stamp) AS time_stamp_max
FROM
lives
GROUP BY
usr_id
) AS l2
...
Rails 3: Get Random Record
...You can use the following trick on an indexed column (PostgreSQL syntax):
select *
from my_table
where id >= trunc(
random() * (select max(id) from my_table) + 1
)
order by id
limit 1;
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Legality of COW std::string implementation in C++11
...be seen in the following if COW were allowed: std::string a("something"); char& c1 = a[0]; std::string b(a); char& c2 = a[1]; c1 is a reference to a. You then "copy" a. Then, when you attempt to take the reference the second time, it has to make a copy to get a non-const reference since...
Adding gif image in an ImageView in android
...= 0; i < 11; i++) {
app += (char) block[i];
}
if (app.equals("NETSCAPE2.0")) {
readNetscapeExt();
} e...
C++使用OLE/COM高速读写EXCEL的源码 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ad = FALSE);
///通过名称使用某个sheet，
BOOL LoadSheet(const TCHAR* sheet,BOOL pre_load = FALSE);
///通过序号取得某个Sheet的名称
CString GetSheetName(long table_index);
///得到Sheet的总数
int GetSheetCount();
///打开文件
BOOL OpenExcelFile(const TCHAR...
Linq code to select one item
I find myself writing a lot of code like this to select one item that matches
7 Answers
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How to copy a row and insert in same table with a autoincrement field in MySQL?
...
Use INSERT ... SELECT:
insert into your_table (c1, c2, ...)
select c1, c2, ...
from your_table
where id = 1
where c1, c2, ... are all the columns except id. If you want to explicitly insert with an id of 2 then include that in your INSER...
getting the ng-object selected with ng-change
Given the following select element
10 Answers
10
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Fastest check if row exists in PostgreSQL
...
Use the EXISTS key word for TRUE / FALSE return:
select exists(select 1 from contact where id=12)
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