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COUNT DISTINCT with CONDITIONS
...me;
The first count(distinct...) is easy.
The second one, looks somewhat complex, is actually the same as the first one, except that you use case...when clause. In the case...when clause, you filter only positive values. Zeros or negative values would be evaluated as null and won't be included in ...
How do I reword the very first git commit message?
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Do git rebase -i --root
(point to root instead of pointing to a specific commit)
This way, the first commit is also included and you can just reword it like any other commit.
The --root option was introduced in Git v1.7.12 (2012). Before then the only option was to use filter-branch or --amend, ...
Rails check if yield :area is defined in content_for
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How can I get the intersection, union, and subset of arrays in Ruby?
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318
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Are static class instances unique to a request or a server in ASP.NET?
...gleton class that stores its instance in HttpContext.Current.Items. (In my common library for ASP.NET, I have a generic SingletonRequest class for this purpose).
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shared_ptr to an array : should it be used?
...ate<class Y> explicit shared_ptr(Y* p);
Requires: Y shall be a complete type. The expression delete[] p, when T is an array type, or delete p, when T is not an array type, shall have well-defined behavior, and shall not throw exceptions.
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Remarks: When T is an array type, this con...
Git branch diverged after rebase
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When you rebase a branch, you have to rewrite the commits for any commit which is above the commits in the branch onto which you are rebasing. This is because one of the properties of a commit is its parent (or parents). When you rebase, you're changing the parent of the old...
JavaScript click event listener on class
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stackoverflow.com/a/13258908/1333493 "document.getElementsByClassName does not return an array. It returns a node list which is traversed like an XML file."
– Nemo
Sep 24 '15 at 10:20
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What is PAGEIOLATCH_SH wait type in SQL Server?
...1> = <value> order by <PrimaryKey>
, check that you have a composite index on (col1, col_primary_key).
If you don't have one, then you'll need either a full INDEX SCAN if the PRIMARY KEY is chosen, or a SORT if an index on col1 is chosen.
Both of them are very disk I/O consuming oper...