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How do you count the number of occurrences of a certain substring in a SQL varchar?
...mparing the lengths
Declare @string varchar(1000)
Set @string = 'a,b,c,d'
select len(@string) - len(replace(@string, ',', ''))
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Python Pandas: Get index of rows which column matches certain value
... [57]: idx
Out[57]: Int64Index([10, 40, 50], dtype='int64')
then you can select the rows using loc instead of iloc:
In [58]: df.loc[idx]
Out[58]:
BoolCol
10 True
40 True
50 True
[3 rows x 1 columns]
Note that loc can also accept boolean arrays:
In [55]: df.loc[df['BoolCol']]
Ou...
What is the difference between precision and scale?
...on. e.g: Precision 4, scale 2 - will fail any number > 99.9999..; try: select cast (99.99999 as NUMBER(4,2)) from dual; //OK; select cast (100.9 as NUMBER(4,2)) from dual; //FAIL;
– Jama Djafarov
Mar 6 '15 at 17:47
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How to make vim paste from (and copy to) system's clipboard?
...system clipboard. On X11 systems both registers can be used. See :help x11-selection for more details, but basically the "* is analogous to X11's _PRIMARY_ selection (which usually copies things you select with the mouse and pastes with the middle mouse button) and "+ is analogous to X11's _CLIPBOAR...
Is there a way to select sibling nodes?
For some performance reasons, I am trying to find a way to select only sibling nodes of the selected node.
13 Answers
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Postgresql aggregate array
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Use array_agg: http://www.sqlfiddle.com/#!1/5099e/1
SELECT s.name, array_agg(g.Mark) as marks
FROM student s
LEFT JOIN Grade g ON g.Student_id = s.Id
GROUP BY s.Id
By the way, if you are using Postgres 9.1, you don't need to repeat the columns on SELECT to GROUP BY,...
“Inspect” a hover element?
...if this is just a problem on my PC or not, but I can't see the menu option selected via keyboard and the shortcut key (ctrl-shift-I) doesn't work while the dropdown menu is visible, so since inspect element is the last option on the dropdown, I used up-arrow key to wrap-around to the last item and h...
Table name as variable
...mpare data between the same tables of different databases:
static query:
SELECT * FROM [DB_ONE].[dbo].[ACTY]
EXCEPT
SELECT * FROM [DB_TWO].[dbo].[ACTY]
since I want easily change tha name of table and schema I have created this dynamic query:
declare @schema varchar(50)
declare @table varchar(5...
“Unresolved inclusion” error with Eclipse CDT for C standard library headers
...lipse, you open the Properties of your project, expand "C/C++ General" and select "Paths and Symbols".
Make sure you have added the include dir for each language you are using. (In my case, I needed to just add it to GNU C++.)
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Vim indent xml file
... that you don't have to alter your vimrc file. Plus it is easier to format select portions of the XML file (something I happen to do a lot).
First, highlight the XML you want to format.
Then, in normal mode, type ! xmllint --format -
Your command-line at the bottom will look like this:
:'<,'&...