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MySQL, Check if a column exists in a table with SQL
I am trying to write a query that will check if a specific table in MySQL has a specific column, and if not — create it. Otherwise do nothing. This is really an easy procedure in any enterprise-class database, yet MySQL seems to be an exception.
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round() for float in C++
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It's available since C++11 in cmath (according to http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf)
#include <cmath>
#include <iostream>
int main(int argc, char** argv) {
std::cout << "r...
Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the La
The error in the title is thrown only in Google Chrome, according to my tests. I'm base64 encoding a big XML file so that it can be downloaded:
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Remove not alphanumeric characters from string
...put.replace(/\W/g, '')
Note that \W is the equivalent of [^0-9a-zA-Z_] - it includes the underscore character. To also remove underscores use e.g.:
input.replace(/[^0-9a-z]/gi, '')
The input is malformed
Since the test string contains various escaped chars, which are not alphanumeric, it will ...
Is there a way to crack the password on an Excel VBA Project?
...e some Excel 2003 macros, but the VBA projects are password protected, and it seems there's a lack of documentation... no-one knows the passwords.
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Linux command or script counting duplicated lines in a text file?
If I have a text file with the following conent
8 Answers
8
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用App Inventor 2做扫描仪App？从拍照到展示，手把手教你搭一套完整相机功...
用App Inventor 2做扫描仪App？从拍照到展示，手把手教你搭一套完整相机功能
上周有个做社区志愿服务的朋友问我："能不能用手机拍下老人的健康档案，然后直接在App里分类显示？"他需要一个轻量的、不给老人增加学习...
Determine command line working directory when running node bin script
I am creating a node command line interface. It is installed globally and uses a bin file to execute.
5 Answers
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Underscore: sortBy() based on multiple attributes
I am trying to sort an array with objects based on multiple attributes. I.e if the first attribute is the same between two objects a second attribute should be used to comapare the two objects. For example, consider the following array:
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Underscore prefix for property and method names in JavaScript
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Welcome to 2019!
It appears a proposal to extend class syntax to allow for # prefixed variable to be private was accepted. Chrome 74 ships with this support.
_ prefixed variable names are considered private by convention but are still public...