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count(*) vs count(column-name) - which is more correct? [duplicate]
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there is a performance difference (at least in MySQL) as well (see my answer).
– nickf
Jun 9 '10 at 7:51
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中文网（自研/维护）拓展 · App Inventor 2 中文网
...果是则返回’真’，否则返回’假’。
ResetFirstRun()
重置App的运行状态为第一次运行。
SystemSettings()
跳转到系统设置界面
WirelessSettings()
跳转到无线和网络设置界面
AirPlaneState
Component for AirPlaneState
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What resources exist for Database performance-tuning? [closed]
...er to a not-the-same-inquiry is probably a good start.
Hidden Features of MySQL
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How can I convert bigint (UNIX timestamp) to datetime in SQL Server?
...our code must match the casing! Another point could be that your System is MySql, than the name is date_add(). Regards ;)
– Nightking
Feb 11 '17 at 10:15
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How to change the name of a Django app?
...E <oldAppName>_modelName RENAME TO <newAppName>_modelName. For mysql too I think it is the same (as mentioned by @null_radix)
(For Django >= 1.7) Update the django_migrations table to avoid having your previous migrations re-run: UPDATE django_migrations SET app='<NewAppName>' W...
What's the difference between using INDEX vs KEY in MySQL?
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Here is a nice description about the "difference":
"MySQL requires every Key also be indexed, that's an implementation
detail specific to MySQL to improve performance."
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What's the difference between MyISAM and InnoDB? [duplicate]
...c engines you asked about (InnoDB and MyISAM) have different design goals. MySQL also has other storage engines, with their own design goals.
So, in choosing between InnoDB and MyISAM, the first step is in determining if you need the features provided by InnoDB. If not, then MyISAM is up for conside...
How to use GROUP_CONCAT in a CONCAT in MySQL
If I have a table with the following data in MySQL:
7 Answers
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c++ 代码提升权限，请求管理员身份运行权限 - C/C++ - 清泛网 - 专注C/C++及内核技术
...CreateProcess函数，有时会遇到权限不足失败的情况，那么如何提升执行权限呢？使用ShellExecuteEx函数： ------ 普通的启动一个程序使用CreateProcess函数，有时会遇到权限不足失败的情况，那么如何提升执行权限呢？
使用 ShellExecut...
Why does MYSQL higher LIMIT offset slow the query down?
...30
) q
JOIN mytable t
ON t.id = q.id
See this article:
MySQL ORDER BY / LIMIT performance: late row lookups
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