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List all tables in postgresql information_schema
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You should be able to just run select * from information_schema.tables to get a listing of every table being managed by Postgres for a particular database.
You can also add a where table_schema = 'information_schema' to see just the tables in the informat...
Error while installing json gem 'mkmf.rb can't find header files for ruby'
...installing command-line tools and accepting the license with
sudo xcode-select --install
sudo xcodebuild -license accept
The issue is that Xcode 11 ships the macOS 10.15 SDK which includes headers for ruby2.6, but not for macOS 10.14's ruby2.3. You can verify that this is your problem by runnin...
MySQL DISTINCT on a GROUP_CONCAT()
I am doing SELECT GROUP_CONCAT(categories SEPARATOR ' ') FROM table . Sample data below:
6 Answers
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How do I get the value of text input field using JavaScript?
... 'searchtext' in your page.
Method 5:
Use the powerful document.querySelector('selector').value which uses a CSS selector to select the element
For example, document.querySelector('#searchTxt').value; selected by id
document.querySelector('.searchField').value; selected by class
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Different ways of adding to Dictionary
...to know how it works especially if you work with dictionaries of string or char type of key. It's case sensitive because of undergoing hashing. So for example "name" != "Name". Let's use our CRC32 to depict this.
Value for "name" is: e04112b1
Value for "Name" is: 1107fb5b
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How to select the first element with a specific attribute using XPath
The XPath bookstore/book[1] selects the first book node under bookstore .
9 Answers
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How dangerous is it to compare floating point values?
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[The 'right answer' glosses over selecting K. Selecting K ends up being just as ad-hoc as selecting VISIBLE_SHIFT but selecting K is less obvious because unlike VISIBLE_SHIFT it is not grounded on any display property. Thus pick your poison - select K or s...
Easiest way to detect Internet connection on iOS?
...std.h>
#include<netdb.h>
Code:
-(BOOL)isNetworkAvailable
{
char *hostname;
struct hostent *hostinfo;
hostname = "google.com";
hostinfo = gethostbyname (hostname);
if (hostinfo == NULL){
NSLog(@"-> no connection!\n");
return NO;
}
else{
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SQL Server: Difference between PARTITION BY and GROUP BY
...y're used in different places. group by modifies the entire query, like:
select customerId, count(*) as orderCount
from Orders
group by customerId
But partition by just works on a window function, like row_number:
select row_number() over (partition by customerId order by orderId)
as OrderN...
What is the difference between string primitives and String objects in JavaScript?
...plains the much faster random access speed.
So what happens when you do s.charAt(i) for instance?
Since s is not an instance of String, JavaScript will auto-box s, which has typeof string to its wrapper type, String, with typeof object or more precisely s.valueOf(s).prototype.toString.call = [obje...