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PostgreSQL - max number of parameters in “IN” clause?
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explain select * from test where id in (values (1), (2));
QUERY PLAN
Seq Scan on test (cost=0.00..1.38 rows=2 width=208)
Filter: (id = ANY ('{1,2}'::bigint[]))
But if try 2nd query:
explain select * from test where id = an...
How to select a CRAN mirror in R
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Repository selection screen cannot be shown on your system (OS X), since OS X no longer includes X11. R tries to show you the prompt through X11. Install X11 from http://xquartz.macosforge.org/landing/. Then run the install command. The...
SQL statement to get column type
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Using SQL Server:
SELECT DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE
TABLE_NAME = 'yourTableName' AND
COLUMN_NAME = 'yourColumnName'
share
|...
正确重置MySQL密码 - 爬虫/数据库 - 清泛IT社区，为创新赋能！
谁都不想弄丢家门钥匙，但不管多么小心，时间长了，这样的事情总会发生几次。MySQL密码也是一样，把它写在文档上不太安全，记在脑子里又难免会忘记。如果你忘记了MySQL密码，如何重置它呢？
下面是错误答案：首先停止MyS...
解决IIS发布时global_asax的dll 的CS0433冲突问题 - 环境配置 - 清泛IT社区，为创新赋能！
Server Error in '/' Application.Compilation ErrorDescription: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.
Compiler Error Message: CS0433: The type 'ASP.globa...
自定义下载器扩展：个性化下载进度展示 - App Inventor 2 拓展 - 清泛IT社...
Customdownloader Extension
Documentation
Event triggered when an error occurs during download.
Successful Download downloadId, filePath, fileSize, fileName
Event triggered to report download progress, speed, eta, fileSize, and downloadedSize
Download the file of given URL to t...
mobile location - App应用开发 - 清泛IT社区，为创新赋能！
通过android studio实现: 在屏幕上输入手机号码，点击确定开始查找，用gps数据确定手机的当前精确位置，精确度5米，找到后把经纬度写在两个文字框里，并在百度地图上标注出位置,并移动到屏幕中央，放大地图。
Imple...
Finding duplicate values in MySQL
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Do a SELECT with a GROUP BY clause. Let's say name is the column you want to find duplicates in:
SELECT name, COUNT(*) c FROM table GROUP BY name HAVING c > 1;
This will return a result with the name value in the first colum...
What is the difference between D3 and jQuery?
... web app plugins.
Both are JavaScript DOM manipulation libraries, have CSS selectors and fluent API and are based on web standards which makes them look similar.
Following code is an example of D3 usage which is not possible with jQuery (try it in jsfiddle):
// create selection
var selection ...
SQL NVARCHAR and VARCHAR Limits
... large (unavoidable) dynamic SQL query. Due to the number of fields in the selection criteria the string containing the dynamic SQL is growing over 4000 chars. Now, I understand that there is a 4000 max set for NVARCHAR(MAX) , but looking at the executed SQL in Server Profiler for the statement
...