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How do I get SUM function in MySQL to return '0' if no values are found?
...
Use COALESCE to avoid that outcome.
SELECT COALESCE(SUM(column),0)
FROM table
WHERE ...
To see it in action, please see this sql fiddle: http://www.sqlfiddle.com/#!2/d1542/3/0
More Information:
Given three tables (one with all numbers, one with all nul...
Difference between Ctrl+Shift+F and Ctrl+I in Eclipse
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Ctrl+Shift+F formats the selected line(s) or the whole source code if you haven't selected any line(s) as per the formatter specified in your Eclipse, while Ctrl+I gives proper indent to the selected line(s) or the current line if you haven't selecte...
How do I check to see if a value is an integer in MySQL?
...e REGEXP operator, matching the string to a regular expression. Simply do
select field from table where field REGEXP '^-?[0-9]+$';
this is reasonably fast. If your field is numeric, just test for
ceil(field) = field
instead.
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Export specific rows from a PostgreSQL table as INSERT SQL script
...d line utility pg_dump to export to a file:
create table export_table as
select id, name, city
from nyummy.cimory
where city = 'tokyo'
$ pg_dump --table=export_table --data-only --column-inserts my_database > data.sql
--column-inserts will dump as insert commands with column names.
--data-...
Is there any way to create a blank solution (.sln) file first and then add projects?
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Creating Solutions To create a new
solution
On the File menu, select New and then click Project.
In the Project types pane, select Other Project Types and
then select Visual Studio
Solutions.
In the Templates pane, select Blank Solution.
Enter a name for the project.
To chan...
Select Pandas rows based on list index
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For large datasets, it is memory efficient to read only selected rows via the skiprows parameter.
Example
pred = lambda x: x not in [1, 3]
pd.read_csv("data.csv", skiprows=pred, index_col=0, names=...)
This will now return a DataFrame from a file that skips all rows except 1 and ...
What's the difference between MyISAM and InnoDB? [duplicate]
... on the table, and while that lock is held, no other session can perform a SELECT or a DML operation on the table.
Those two specific engines you asked about (InnoDB and MyISAM) have different design goals. MySQL also has other storage engines, with their own design goals.
So, in choosing between In...
Heroku/GoDaddy: send naked domain to www [closed]
....com to www.yourdomain.com.
Here's how.
Within Account Manager, select My Domain Names
Select the domain name that you want to manage
In the green box, select Change Where Domain Points
Select Advanced DNS, then Continue
First, edit the A Records by selecting Edit A Records
F...
Tri-state Check box in HTML?
...lternative would be to play with the checkbox transparency
for the "some selected" state (as Gmail does used to
do in previous versions). It will require some javascript and a CSS
class. Here I put a particular example that handles a list with
checkable items and a checkbox that allows to se...
How do I get a list of column names from a psycopg2 cursor?
I would like a general way to generate column labels directly from the selected column names, and recall seeing that python's psycopg2 module supports this feature.
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