大约有 40,000 项符合查询结果（耗时：0.0315秒） [XML]
How to pull a random record using Django's ORM?
...on't know about other databases).
order_by('?')[:N] will be translated to SELECT ... FROM ... WHERE ... ORDER BY RAND() LIMIT N query.
It means that for every row in table the RAND() function will be executed, then the whole table will be sorted according to value of this function and then first N...
How can I clear the SQL Server query cache?
...et DBID from one database name first
DECLARE @intDBID INT;
SET @intDBID = (SELECT [dbid]
FROM master.dbo.sysdatabases
WHERE name = N'AdventureWorks2014');
DBCC FLUSHPROCINDB (@intDBID);
7. Clear plan cache for the current database
USE AdventureWorks2014;
GO
-- New...
How can I select and upload multiple files with HTML and PHP, using HTTP POST?
... </body>
</html>
Here's what it looks like in Chrome after selecting 2 items in the file dialog:
And here's what it looks like after clicking the "Upload" button.
This is just a sketch of a fully working answer. See PHP Manual: Handling file uploads for more information on prop...
Convert timestamp to date in MySQL query
...
SELECT * FROM users WHERE DATE_FORMAT(FROM_UNIXTIME(users.user_created_at),'%Y-%b-%e') = '2015-03-06' is this correct format or should i modify this?
– Dheeraj Thedijje
Mar 7 '18 at 11:4...
How to show the last queries executed on MySQL?
...the result in this way, but parameters are present by question mark, e.g., select foo from bar where x=?. How can I get the complete query?
– petertc
Nov 4 '15 at 5:52
...
IN vs OR in the SQL WHERE Clause
...h are nearly instant. When the column is not indexed I got these results:
SELECT COUNT(*) FROM t_inner WHERE val IN (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000);
1 row fetched in 0.0032 (1.2679 seconds)
SELECT COUNT(*) FROM t_inner WHERE val = 1000 OR val = 2000 OR val = 3000 OR val = 40...
Plurality in user messages
... are wrong. The correct way of doing this is:
string message = ( noofitemsselected==1 ?
"You have selected " + noofitemsselected + " item. Are you sure you want to delete it?":
"You have selected " + noofitemsselected + " items. Are you sure you want to delete them?"
);
This is because differ...
Ruby: Can I write multi-line string with no concatenation?
... HEREDOC syntax (via this link):
p <<END_SQL.gsub(/\s+/, " ").strip
SELECT * FROM users
ORDER BY users.id DESC
END_SQL
# >> "SELECT * FROM users ORDER BY users.id DESC"
The latter would mostly be for situations that required more flexibility in the processing. I personall...
How to swap the buffers in 2 windows emacs
...
If you just want to swap windows (independent on the selected one), you can use the following (defun win-swap () "Swap windows using buffer-move.el" (interactive) (if (null (windmove-find-other-window 'right)) (buf-move-left) (buf-move-right)))
...
Using Emacs to recursively find and replace in text files not already open
...files, type D to close them all.
Step-by-Step Guide for Emacs Beginners
Select Target Files
Start emacs by typing “emacs” in the command line interface prompt. (Or, double click the Emacs icon if you are in a Graphics User Interface environment)
Selecting Files in a Directory
First you nee...