大约有 40,000 项符合查询结果（耗时：0.0309秒） [XML]
MYSQL OR vs IN performance
...for future Googlers. Total count of returned results is 7264 out of 10000
SELECT * FROM item WHERE id = 1 OR id = 2 ... id = 10000
This query took 0.1239 seconds
SELECT * FROM item WHERE id IN (1,2,3,...10000)
This query took 0.0433 seconds
IN is 3 times faster than OR
...
How can foreign key constraints be temporarily disabled using T-SQL?
...use this script to list the constraint status. Will be very helpfull:
SELECT (CASE
WHEN OBJECTPROPERTY(CONSTID, 'CNSTISDISABLED') = 0 THEN 'ENABLED'
ELSE 'DISABLED'
END) AS STATUS,
OBJECT_NAME(CONSTID) AS CONSTRAINT_NAME,
OBJECT_NAME(FKEYID) AS TABLE_NAM...
Show an image preview before upload
... code snippet in the HTML example below filters out images from the user's selection and renders selected files into multiple thumbnail previews:
function handleFileSelect(evt) {
var files = evt.target.files;
// Loop through the FileList and render image files as thumbnails.
fo...
CSS Selector that applies to elements with two classes
Is there a way to select an element with CSS based on the value of the class attribute being set to two specific classes. For example, let's say I have 3 divs:
...
What are good grep tools for Windows? [closed]
... than PowerGREP.)
Additional solutions
Existing Windows commands
FINDSTR
Select-String in PowerShell
Linux command implementations on Windows
Cygwin
Cash
Grep tools with a graphical interface
AstroGrep
BareGrep
GrepWin
Additional Grep tools
dnGrep
...
How do I alter the position of a column in a PostgreSQL database table?
... tablename (column defs go here);
insert into tablename (col1, col2, col3) select col1, col2, col3 from oldtable;
share
|
improve this answer
|
follow
|
...
How can I convert bigint (UNIX timestamp) to datetime in SQL Server?
...
SET @AdjustedLocalDatetime = @Datetime - @LocalTimeOffset
RETURN (SELECT DATEADD(second,@AdjustedLocalDatetime, CAST('1970-01-01 00:00:00' AS datetime)))
END;
GO
share
|
improve this answe...
How to find the mysql data directory from command line in windows
... the following command line:
mysql -s -N -uUSER -p information_schema -e 'SELECT Variable_Value FROM GLOBAL_VARIABLES WHERE Variable_Name = "datadir"'
The command will select the value only from mysql's internal information_schema database and disables the tabular output and column headers.
Outp...
iPhone app signing: A valid signing identity matching this profile could not be found in your keycha
...
Open Xcode. Click WINDOW > ORGANIZER. Then click the Devices tab and select "Provisioning Profiles" on the left.
That should bring up your provisioning profiles. Highlight one by one (if more than 1), right click and delete profile. Yes, just do it! Delete them all! (I kept making a new one a...
Sqlite: CURRENT_TIMESTAMP is in GMT, not the timezone of the machine
...a unix
timestamp 1092941466, and compensate
for your local timezone.
SELECT datetime(1092941466, 'unixepoch', 'localtime');
That didn't look like it fit my needs, so I tried changing the "datetime" function around a bit, and wound up with this:
select datetime(timestamp, 'localtime')
That...