大约有 5,680 项符合查询结果（耗时：0.0214秒） [XML]
SQL “select where not in subquery” returns no results
...you get a table scan but @patmortech's query is still twice as fast (for a 100K row master table).
If neither are indexed on commonID, you get two table scans and the difference is negligible.
If both are indexed on commonID, the "not exists" query runs in 1/3 the time.
...
What is ActiveMQ used for - can we apply messaging concept using a Database?
...a system that process client requests. In normal cases the system receives 100 requests per minute. This system is unreliable when number of request goes beyond average. In such case Queue can manage requests and it can push messages periodically based on system throughput without breaking it.
Asyn...
Can I restore a single table from a full mysql mysqldump file?
...lly huge db it is can very weird - restore 150 GB of data for one table of 100 MB.
– Enyby
Jul 7 '16 at 21:02
I just r...
Best approach to remove time part of datetime in SQL Server
...rrelevant because they are already VERY fast. Unless I had record sets of 100,000 or more, I couldn't even get the CPU Time to read above zero.
Considering the fact that DateAdd is meant for this purpose and is more robust, I'd say use DateAdd.
...
Distributed sequence number generation?
...
+100
OK, this is a very old question, which I'm first seeing now.
You'll need to differentiate between sequence numbers and unique IDs t...
SQL Joins Vs SQL Subqueries (Performance)?
...at will help a lot...) among other things.
The only REAL way to tell with 100% certainty which is faster is to turn on performance tracking (IO Statistics is especially useful) and run them both. Make sure to clear your cache between runs!
...
Locking a file in Python
...
+100
Alright, so I ended up going with the code I wrote here, on my website link is dead, view on archive.org (also available on GitHub)....
How to move an iFrame in the DOM without losing its state?
...tion(){
document.getElementsByTagName('body')[0].appendChild(wrap1);
},10000);
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Using Default Arguments in a Function
...; 'cow.png',
'alt' => 'milk factory',
'height' => 100,
'width' => 50
);
$img = array_merge($defaults, $img);
/* ... */
}
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width:auto for fields
.... The default size is what's driving the auto width.
You could try width:100% as illustrated in my example below.
Doesn't fill width:
<form action='' method='post' style='width:200px;background:khaki'>
<input style='width:auto' />
</form>
Fills width:
<form action='' me...