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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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Reference — What does this symbol mean in PHP?
...nd y have the same key/value pairs
in the same order and of the same types
x !== y Non-identity True if x is not identical to y
++ x Pre-increment Increments x by one, then returns x
x ++ Post-increment Returns x, then increments x by one
-- x Pr...
搭建高可用mongodb集群（二）—— 副本集 - 大数据 & AI - 清泛网 - 专注C/...
...搭建高可用MongoDB集群（一）——配置MongoDB》提到了几个问题还没有解决。主节点挂了能否自动切换连接？目前需要手工切换。 在上一篇文章《搭建高可用MongoDB集群（一）——配置MongoDB》 提到了几个问题还没有解决。
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Synchronous request in Node.js
If I need to call 3 http API in sequential order, what would be a better alternative to the following code:
18 Answers
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笨法玩电商网站秒杀 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...跟不上，程序就会堆积大量连接，这可能会引起很多连锁问题：一方面可能导致内存不足，以PHP为例，一个连接通常占用10M左右，堆积一千个连接的话，10G内存就没有了；另一方面大量的连接可能耗尽端口资源，具体取决于内核...
Deprecated: mysql_connect()
...arning isn't ideal but it should still be done to keep the code in working order. A good developer will still keep track of deprecated code and schedule it for a future update.
– sturrockad
Jan 8 '15 at 11:23
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“Notice: Undefined variable”, “Notice: Undefined index”, and “Notice: Undefined offset” using PHP
...hough PHP does not require a variable declaration, it does recommend it in order to avoid some security vulnerabilities or bugs where one would forget to give a value to a variable that will be used later in the script. What PHP does in the case of undeclared variables is issue a very low level erro...
C++特化模板函数的符号多重定义错误问题 - C/C++ - 清泛网 - 专注C/C++及内核技术
C++特化模板函数的符号多重定义错误问题error LNK2005: "void __stdcall SerializeElements<class CLogEvent> ...fatal error LNK1169: 找到一个或多个多重定义的符号.我...特化模板函数SerializeElements时，报重复定义的错误，如下：
error LNK2005: "void __std...
Determining Referer in PHP
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How to delete a file via PHP?
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