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How do I get SUM function in MySQL to return '0' if no values are found?
...e 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 nulls, and one with a mixture):
SQL Fiddle...
Can you use an alias in the WHERE clause in mysql?
I need to use an alias in the WHERE clause, but It keeps telling me that its an unknown column. Is there any way to get around this issue? I need to select records that have a rating higher than x. Rating is calculated as the following alias:
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Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?
I have the following table:
4 Answers
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Is key-value observation (KVO) available in Swift?
...e any key differences that weren't otherwise present when using key-value observation in Objective-C?
11 Answers
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What does 'synchronized' mean?
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The synchronized keyword is all about different threads reading and writing to the same variables, objects and resources. This is not a trivial topic in Java, but here is a quote from Sun:
synchronized methods enable a simple
strategy for preventing t...
SQL Server - transactions roll back on error?
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You can put set xact_abort on before your transaction to make sure sql rolls back automatically in case of error.
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List tables in a PostgreSQL schema
When I do a \dt in psql I only get a listing of tables in the current schema ( public by default).
4 Answers
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HTML input - name vs. id [duplicate]
When using the HTML <input> tag, what is the difference between the use of the name and id attributes especially that I found that they are sometimes named the same?
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AngularJS $resource RESTful example
I would like to use $resource to call my RESTful web service, (which I am still working on) but I would like to find out if I got my AngularJS script correct first.
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SVG gradient using CSS
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Just use in the CSS whatever you would use in a fill attribute.
Of course, this requires that you have defined the linear gradient somewhere in your SVG.
Here is a complete example:
rect {
cursor: pointer;
shape-rendering: crispEdges;
fill: url(#MyGradient);
}
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