大约有 40,000 项符合查询结果（耗时：0.0363秒） [XML]
Is it better in C++ to pass by value or pass by constant reference?
...ractice1 to use pass by const ref for all types, except for builtin types (char, int, double, etc.), for iterators and for function objects (lambdas, classes deriving from std::*_function).
This was especially true before the existence of move semantics. The reason is simple: if you passed by value...
How can we match a^n b^n with Java regex?
...finalized pattern, with additional test cases, including one that's 10,000 characters long:
$tests = array(
'aaa', 'aaab', 'aaaxb', 'xaaab', 'b', 'abbb', 'aabb', 'aaabbbbb', 'aaaaabbb',
'', 'ab', 'abb', 'aab', 'aaaabb', 'aaabbb', 'bbbaaa', 'ababab', 'abc',
str_repeat('a', 5000).str_repeat('b',...
How to call a stored procedure from Java and JPA
...s (
postId IN NUMBER,
commentCount OUT NUMBER )
AS
BEGIN
SELECT COUNT(*) INTO commentCount
FROM post_comment
WHERE post_id = postId;
END;
You can call it from JPA as follows:
StoredProcedureQuery query = entityManager
.createStoredProcedureQuery("count_comments"...
IN vs OR in the SQL WHERE Clause
...h are nearly instant. When the column is not indexed I got these results:
SELECT COUNT(*) FROM t_inner WHERE val IN (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000);
1 row fetched in 0.0032 (1.2679 seconds)
SELECT COUNT(*) FROM t_inner WHERE val = 1000 OR val = 2000 OR val = 3000 OR val = 40...
How do I perform the SQL Join equivalent in MongoDB?
...background as well, I would appreciate MongoDB taking a 'result set' (with selected returned fields) as input for a new query in one go, much like nested queries in SQL
– Stijn Sanders
Nov 26 '10 at 23:17
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Difference between Select and ConvertAll in C#
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Select is a LINQ extension method and works on all IEnumerable<T> objects whereas ConvertAll is implemented only by List<T>. The ConvertAll method exists since .NET 2.0 whereas LINQ was introduced with 3.5.
You s...
HTML - Display image after selecting filename [duplicate]
I have a form that allows me with
3 Answers
3
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Eclipse git checkout (aka, revert)
...ing" view, right click the deleted file in the "Unstaged Changes" list and select "Replace with HEAD Revision"
– Vlasta Dolejs
Sep 5 '17 at 8:03
add a comment
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Search for selection in vim
...
Check this Vim tip: Search for visually selected text
Or you can simply yank the selected text with y and go to search mode /, then you can paste the last yanked text with Ctrl+R 0
share
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GROUP_CONCAT ORDER BY
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You can use ORDER BY inside the GROUP_CONCAT function in this way:
SELECT li.client_id, group_concat(li.percentage ORDER BY li.views ASC) AS views,
group_concat(li.percentage ORDER BY li.percentage ASC)
FROM li GROUP BY client_id
...