大约有 15,000 项符合查询结果（耗时：0.0208秒） [XML]
Coding Practices which enable the compiler/optimizer to make a faster program
...Arithmetic (Edited: applied code format to code fragment, added example)
Convert if statements into boolean assignments. Some processors can conditionally execute instructions without branching:
bool status = true;
status = status && /* first test */;
status = status && /* second...
When to use Common Table Expression (CTE)
...ing well? Can someone give me a simple example of limitations with regular select, derived or temp table queries to make the case of CTE? Any simple examples would be highly appreciated.
...
What is the simplest SQL Query to find the second largest value?
...
SELECT MAX( col )
FROM table
WHERE col < ( SELECT MAX( col )
FROM table )
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How do I use variables in Oracle SQL Developer?
... other stuff didn't work for me, but this did:
define value1 = 'sysdate'
SELECT &&value1 from dual;
Also it's the slickest way presented here, yet.
(If you omit the "define"-part you'll be prompted for that value)
...
Is it possible for git-merge to ignore line-ending differences?
...r merge respecting eol, KDiff3 is better than DiffMerge (which will always convert LF into CRLF)
# KDiff3 will display eol choices (if Windows: CRLF, if Unix LF)
"C:/Program Files/KDiff3/kdiff3.exe" -m "$base" "$alocal" "$remote" -o "$result"
else
#there is not always a common ancestor: ...
How do I use ROW_NUMBER()?
...
For the first question, why not just use?
SELECT COUNT(*) FROM myTable
to get the count.
And for the second question, the primary key of the row is what should be used to identify a particular row. Don't try and use the row number for that.
If you returned Ro...
Tool for comparing 2 binary files in Windows [closed]
...
I prefer to use objcopy to convert to hex, then use diff.
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How do SQL EXISTS statements work?
... criteria -- this is why it can be faster than IN. Also be aware that the SELECT clause in an EXISTS is ignored - IE:
SELECT s.*
FROM SUPPLIERS s
WHERE EXISTS (SELECT 1/0
FROM ORDERS o
WHERE o.supplier_id = s.supplier_id)
...should hit a division by zero error...
Switch statement fallthrough in C#?
...ing and during maintenance.
Now, switch could always have been compiled by converting it into the equivalent chain of if-else blocks or similar, but it was designed as allowing compilation into a particular common assembly pattern where one takes a value, computes an offset from it (whether by looki...
Use latest version of Internet Explorer in the webbrowser control
...ss Not found");
return;
}
string FindAppkey = Convert.ToString(Regkey.GetValue(appName));
// Check if key is already present
if (FindAppkey == "8000")
{
MessageBox.Show("Required Application Settings Present");
Regkey.Clos...