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How do write IF ELSE statement in a MySQL query
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150
You probably want to use a CASE expression.
They look like this:
SELECT col1, col2, (case wh...
How to change facet labels?
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128
Change the underlying factor level names with something like:
# Using the Iris data
> i &l...
How do you know when to use fold-left and when to use fold-right?
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105
You can transfer a fold into an infix operator notation (writing in between):
This example fo...
What is the significance of 1/1/1753 in SQL Server?
Why 1753? What do they have against 1752? My great great great great great great great grandfather would be very offended.
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Linux command to list all available commands and aliases
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You can use the bash(1) built-in compgen
compgen -c will list all the commands you could run.
compgen -a will list all the aliases you could run.
compgen -b will list all the built-ins you could run.
compgen -k will list all the keywords you co...
Get Image Height and Width as integer values?
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197
Try like this:
list($width, $height) = getimagesize('path_to_image');
Make sure that:
You...
Reusable library to get human readable version of file size?
... unit in ['','Ki','Mi','Gi','Ti','Pi','Ei','Zi']:
if abs(num) < 1024.0:
return "%3.1f%s%s" % (num, unit, suffix)
num /= 1024.0
return "%.1f%s%s" % (num, 'Yi', suffix)
Supports:
all currently known binary prefixes
negative and positive numbers
numbers larger tha...
Add unique constraint to combination of two columns
...TER TABLE dbo.yourtablename
ADD CONSTRAINT uq_yourtablename UNIQUE(column1, column2);
or
CREATE UNIQUE INDEX uq_yourtablename
ON dbo.yourtablename(column1, column2);
Of course, it can often be better to check for this violation first, before just letting SQL Server try to insert the row and...