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Linux command (like cat) to read a specified quantity of characters
...the chars in line 5 and chars 5 to 8 of line 5,
Note: tail -1 is used to select the last line displayed by the head.
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ORA-00979 not a group by expression
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You must put all columns of the SELECT in the GROUP BY or use functions on them which compress the results to a single value (like MIN, MAX or SUM).
A simple example to understand why this happens: Imagine you have a database like this:
FOO BAR
0 A
0 ...
how to implement regions/code collapse in javascript
....Collections
Public Module JsMacros
Sub OutlineRegions()
Dim selection As EnvDTE.TextSelection = DTE.ActiveDocument.Selection
Const REGION_START As String = "//#region"
Const REGION_END As String = "//#endregion"
selection.SelectAll()
Dim text As Strin...
Server.UrlEncode vs. HttpUtility.UrlEncode
...c.ToString()),
}
where diff.UrlEncode != diff.EscapeDataString
select diff;
foreach (var diff in diffs)
Console.WriteLine($"{diff.Original}\t{diff.UrlEncode}\t{diff.EscapeDataString}");
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How do I copy a string to the clipboard on Windows using Python?
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Get contents of clipboard: result = r.selection_get(selection = "CLIPBOARD")
– majgis
Jul 13 '11 at 3:19
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What are DDL and DML?
...als with data
manipulation, and includes most common SQL statements such SELECT,
INSERT, UPDATE, DELETE etc, and it is used to store, modify, retrieve,
delete and update data in database.
SELECT – retrieve data from the a database
INSERT – insert data into a table
UPDATE – up...
What is “rvalue reference for *this”?
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If a class instance is not const, overload resolution will preferentially select the non-const version. If the instance is const, the user can only call the const version. And the this pointer is a const pointer, so the instance cannot be changed.
What "r-value reference for this` does is allow yo...
Quickly reading very large tables as dataframes
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# sqldf as on SO
f <- file("test.csv")
system.time(SQLf <- sqldf("select * from f", dbname = tempfile(), file.format = list(header = T, row.names = F)))
## user system elapsed
## 10.21 0.47 10.73
ff / ffdf
require(ff)
system.time(FFDF <- read.csv.ffdf(file="test.csv",nro...
Disabling Chrome cache for website development
...ck (or hold left click) on the reload button at the top of the browser and select "Empty Cache and Hard Reload."
This will go beyond "Hard Reload" to empty the cache entirely, ensuring that anything downloaded via javascript or etc. will also avoid using the cache. You don't have to mess with set...
How to use GROUP BY to concatenate strings in MySQL?
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SELECT id, GROUP_CONCAT(name SEPARATOR ' ') FROM table GROUP BY id;
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat
From the link above, GROUP_CONCAT: This function returns a string res...