大约有 43,000 项符合查询结果（耗时：0.0424秒） [XML]
Using group by on multiple columns
..., to do with who is attending what subject at a university:
Table: Subject_Selection
+---------+----------+----------+
| Subject | Semester | Attendee |
+---------+----------+----------+
| ITB001 | 1 | John |
| ITB001 | 1 | Bob |
| ITB001 | 1 | Mickey |
| ITB001 ...
What's the difference between KeyDown and KeyPress in .NET?
...ctical difference between KeyDown and KeyPress is that KeyPress relays the character resulting from a keypress, and is only called if there is one.
In other words, if you press A on your keyboard, you'll get this sequence of events:
KeyDown: KeyCode=Keys.A, KeyData=Keys.A, Modifiers=Keys.None
Key...
How to delete duplicates on a MySQL table?
...n an index is going to be slow for large tables. Wouldn't it be better to SELECT MAX(ID) FROM t GROUP BY unique and then JOIN to an exact match of ID to MAX(ID)?
– ebyrob
Nov 10 '16 at 16:31
...
Oracle SQL Query for listing all Schemas in a DB
...
Using sqlplus
sqlplus / as sysdba
run:
SELECT *
FROM dba_users
Should you only want the usernames do the following:
SELECT username
FROM dba_users
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Windbg Step 2 分析程序堆栈实战 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...转载+整理http: www.cnblogs.com killmyday#include"stdafx.h"#include<tchar.h>#ifdef_UNICODE#define_ttol_wtol#else#define_ttolatol#e...转载+整理 http://www.cnblogs.com/killmyday
#include "stdafx.h"
#include <tchar.h>
#ifdef _UNICODE
#define _ttol _wtol
#else
#define _ttol atol
#...
how do I query sql for a latest record date for each user
...
select t.username, t.date, t.value
from MyTable t
inner join (
select username, max(date) as MaxDate
from MyTable
group by username
) tm on t.username = tm.username and t.date = tm.MaxDate
...
Select N random elements from a List in C#
I need a quick algorithm to select 5 random elements from a generic list. For example, I'd like to get 5 random elements from a List<string> .
...
Get top 1 row of each group
...
;WITH cte AS
(
SELECT *,
ROW_NUMBER() OVER (PARTITION BY DocumentID ORDER BY DateCreated DESC) AS rn
FROM DocumentStatusLogs
)
SELECT *
FROM cte
WHERE rn = 1
If you expect 2 entries per day, then this will arbitrarily pick one...
How do I add options to a DropDownList using jQuery?
...lugins,
var myOptions = {
val1 : 'text1',
val2 : 'text2'
};
var mySelect = $('#mySelect');
$.each(myOptions, function(val, text) {
mySelect.append(
$('<option></option>').val(val).html(text)
);
});
If you had lots of options, or this code needed to be run very ...
Return rows in random order [duplicate]
...
SELECT * FROM table
ORDER BY NEWID()
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