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MySQL, update multiple tables with one query
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Take the case of two tables, Books and Orders. In case, we increase the number of books in a particular order with Order.ID = 1002 in Orders table then we also need to reduce that the total number of books available in our stock by the same number in Books table.
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Shuffle two list at once with same order
...nts and documents2 I have the same documents and I need shuffle them in order to keep same order in both lists. I cannot shuffle them separately because each time I shuffle the list, I get other results. That is why I need to shuffle the at once with same order because I need compare them in the ...
Get records with max value for each group of grouped SQL results
...uper-simple way to do this in mysql:
select *
from (select * from mytable order by `Group`, age desc, Person) x
group by `Group`
This works because in mysql you're allowed to not aggregate non-group-by columns, in which case mysql just returns the first row. The solution is to first order the data...
How to order results with findBy() in Doctrine
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The second parameter of findBy is for ORDER.
$ens = $em->getRepository('AcmeBinBundle:Marks')
->findBy(
array('type'=> 'C12'),
array('id' => 'ASC')
);
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Comparing strings by their alphabetical order
I want to compare the two above string by their alphabetic order (which in this case "Project" then "Sunject" as "P" comes before "S").
Does anyone know how to do that in Java?
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How to select only the first rows for each unique value of a column
...th cte as (
select CName, AddressLine,
rank() over (partition by CName order by AddressLine) as [r]
from MyTable
)
select CName, AddressLine
from cte
where [r] = 1
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Accessing a Dictionary.Keys Key through a numeric index
...t = mydict.Keys.ElementAt(mydict.Count -1);
You should not depend on the order of keys in a Dictionary. If you need ordering, you should use an OrderedDictionary, as suggested in this answer. The other answers on this page are interesting as well.
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Factors in R: more than an annoyance?
...y they are useful because model fitting packages like lme4 use factors and ordered factors to differentially fit models and determine the type of contrasts to use. And graphing packages also use them to group by. ggplot and most model fitting functions coerce character vectors to factors, so the res...
How to sort an array in descending order in Ruby
...; while (--len > 0); is copying the pointers to the elements in reverse order if I remember my C correctly, so the array is reversed.
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Sort a list from another list IDs
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docs = docs.OrderBy(d => docsIds.IndexOf(d.Id)).ToList();
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