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How to count occurrences of a column value efficiently in SQL?
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If you're using Oracle, then a feature called analytics will do the trick. It looks like this:
select id, age, count(*) over (partition by age) from students;
If you aren't using Oracle, then you'll need to join back to the counts:
select a.id, a.age, b.age_co...
How to compare two dates?
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@Emadpres: imagine this was typed manually. The past line was typed first, while the present line was typed second... so the past line was entered first, so past < present is True.
– ramcdougal
Mar 20 '17 at 15:50
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How to copy a row and insert in same table with a autoincrement field in MySQL?
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select c1, c2, ...
from your_table
where id = 1
where c1, c2, ... are all the columns except id. If you want to explicitly insert with an id of 2 then include that in your INSERT column list and your SELECT:
insert into your_table (id, c1, c2, ...)
select 2, c1, c2, ...
from your_table
where i...
What is difference between cacerts and keystore?
...he keystore. (Confusingly, the same file format is used for both and it's called a keystore file.)
– Marquis of Lorne
Jul 29 '13 at 23:44
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Test if a class has an attribute?
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to only check if the attribute is present, which is usually all that is needed for parameterless/propertyless attributes, it's cheaper to use .IsDefined, as it will query the metadata, and not deserialize and instantiate the attribute object.
– Lasse V. Karl...
CSS table column autowidth
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Instead of manually adding the '.last' class, you can just do 'td:last-child' as the selector.
– T.Ho
Feb 13 '13 at 0:34
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Aligning a float:left div to center?
I want to have a group of images display horizontally across the page. Each image has a few link below it so I need to put a container around each image/link-group.
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Escaping a forward slash in a regular expression
...s as the delimiter and therefore you don't need to escape it. But AFAIK in all languages, the only special significance the / has is it may be the designated pattern delimiter.
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Python, Matplotlib, subplot: How to set the axis range?
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Call plot(), then ylim() and then savefig().
– therealrootuser
Apr 15 '15 at 4:01
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Force R to stop plotting abbreviated axis labels - e.g. 1e+00 in ggplot2
... being abbreviated - e.g. 1e+00, 1e+01 along the x axis once plotted? Ideally, I want to force R to display the actual values which in this case would be 1,10 .
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