大约有 47,000 项符合查询结果（耗时：0.0490秒） [XML]
LEFT JOIN only first row
...primary key of the joined tabled.
you can play with the inner query (i.e. order+limit) but it must return one primary key of the desired row that will tell the ON the exact row to join.
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How does @synchronized lock/unlock in Objective-C?
...tuff is more complex, but I didn't feel like writing section directives in order build the DWARF3 unwind tables ;-)
– Louis Gerbarg
Aug 1 '09 at 1:33
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.htaccess not working apache
...able Apache mod_rewrite module
a2enmod rewrite
add the following code to /etc/apache2/sites-available/default
AllowOverride All
Restart apache
/etc/init.d/apache2 restart
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Find nearest latitude/longitude with an SQL query
...S(latitude / 57.3), 2)) AS distance
FROM TableName HAVING distance < 25 ORDER BY distance;
where [starlat] and [startlng] is the position where to start measuring the distance.
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Unit tests vs Functional tests
...her.
Then you integrate the 3rd module, then the 4th and 5th in whatever order you or your team see fit, and once all the jigsaw pieces are placed together, comes
(3) System Testing: testing SW as a whole. This is pretty much "Integration testing of all pieces together".
If that's OK, then ...
Difference between JSONObject and JSONArray
...gt;value pairs, tuples or whatever you want to call them)
like {ID : 1}
Order of elements is not important
a JSONObject of {id: 1, name: 'B'} is equal to {name: 'B', id: 1}.
JSONArray:
Contains only series values
like [1, 'value']
Order of values is important
array of [1,'value'] is ...
Linux下部署企业级邮件服务器(postfix + dovecot + extmail) - 开源 & Gith...
...不做修改表示使用[]中的默认值
先将mysql的lib目录加入 /etc/ld.so.conf，然后执行ldconfig命令使其生效，否则填完以下install配置后，会出现错误"bin/postconf: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such f...
Join vs. sub-query
...M foo
GROUP BY moo
HAVING bar LIKE 'SpaceQ%'
) AS temp_foo
ORDER BY bar
You can nest sub-queries in multiple levels. This can help on huge datasets if you have to group or sort the results. Usually the DB-Server creates a temporary table for this, but sometimes you do not need sort...
Best practice to run Linux service as a different user
..., the same is true for other Linux distros which use the init scripts in /etc/init.d .
8 Answers
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What's the difference between IQueryable and IEnumerable
... code), which an IQueryProvider must explore/interpret/compile/whatever in order to generate results.
Having a query expression gives two advantages.
The first advantage is optimization. Because modifiers like 'Where' are included in the query expression, the IQueryProvider can apply otherwise imp...