大约有 40,000 项符合查询结果（耗时：0.0307秒） [XML]
Which SQL query is faster? Filter on Join criteria or Where clause?
...
Performance-wise, they are the same (and produce the same plans)
Logically, you should make the operation that still has sense if you replace INNER JOIN with a LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = ...
Get Image size WITHOUT loading image into memory
...
As the comments allude, PIL does not load the image into memory when calling .open. Looking at the docs of PIL 1.1.7, the docstring for .open says:
def open(fp, mode="r"):
"Open an image file, without loading the raster data"
There ar...
PHP: Convert any string to UTF-8 without knowing the original character set, or at least try
I have an application that deals with clients from all over the world, and, naturally, I want everything going into my databases to be UTF-8 encoded.
...
Does JavaScript have a method like “range()” to generate a range within the supplied bounds?
...
@rodfersou FYI: your example is wrong. stop is not actually the stop / end position but count / distance. (no offense, just to make people aware of the typo)
– F Lekschas
Jul 26 '18 at 2:45
...
Can you test google analytics on a localhost address?
...ersal Analytics - analytics.js
Google released a new version of analytics called "Universal Analytics" (late 2012 or early 2013). As I write, this the program is still in BETA so the above code is still recommended for most users with existing installations of Google Analytics.
However, for new deve...
How can I wait for a thread to finish with .NET?
I've never really used threading before in C# where I need to have two threads, as well as the main UI thread. Basically, I have the following.
...
How do I determine the target architecture of static library (.a) on Mac OS X?
...cutable ppc
Example with archive:
logan:/Users/logan% file /usr/lib/libMallocDebug.a
/usr/lib/libMallocDebug.a: Mach-O universal binary with 2 architectures
/usr/lib/libMallocDebug.a (for architecture i386): current ar archive random library
/usr/lib/libMallocDebug.a (for architecture ppc): ...
How do I install an R package from source?
...nt me along this great tutorial on webscraping NYtimes with R . I would really love to try it. However, the first step is to installed a package called RJSONIO from source.
...
Installing older version of R package
...
To install an older version of a package from source (within R):
packageurl <- "http://cran.r-project.org/src/contrib/Archive/ggplot2/ggplot2_0.9.1.tar.gz"
install.packages(packageurl, repos=NULL, type="source")
If this doesn'...
How to copy a row and insert in same table with a autoincrement field in MySQL?
....)
select c1, c2, ...
from your_table
where id = 1
where c1, c2, ... are all the columns except id. If you want to explicitly insert with an id of 2 then include that in your INSERT column list and your SELECT:
insert into your_table (id, c1, c2, ...)
select 2, c1, c2, ...
from your_table
where i...