大约有 46,000 项符合查询结果（耗时：0.0431秒） [XML]
Not equal != operator on NULL
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As a manual workaround, you could commonly SELECT * FROM MyTable WHERE coalesce(MyColumn, 'x') <> 'x' to assign a constant if it is NULL value, providing you give an appropriate datatype for the sentinel value x (in this case a string/char). This is TSQL syntax ...
How do I convert from BLOB to TEXT in MySQL?
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That's unnecessary. Just use SELECT CONVERT(column USING utf8) FROM..... instead of just SELECT column FROM...
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MySQL - force not to use cache for testing speed of query
...ACHE (MySQL 5.7) option in your query.
(MySQL 5.6 users click HERE )
eg.
SELECT SQL_NO_CACHE * FROM TABLE
This will stop MySQL caching the results, however be aware that other OS and disk caches may also impact performance. These are harder to get around.
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XPath to select Element by attribute value
...he parts in [ ]) shouldn't have slashes immediately before them. Also, to select the Employee element itself, you should leave off the /text() at the end or otherwise you'd just be selecting the whitespace text values immediately under the Employee element.
//Employee[@id='4']
Edit: As Jens poin...
%Like% Query in spring JpaRepository
...hars as well as a space char following like in your query, as in
@Query("Select c from Registration c where c.place like %:place%").
Cf. http://docs.spring.io/spring-data/jpa/docs/current/reference/html.
You may want to get rid of the @Queryannotation alltogether, as it seems to resemble the st...
Delete branches in Bitbucket
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in Bitbucket go to branches in left hand side menu.
Select your branch you want to delete.
Go to action column, click on three dots (...) and select delete.
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Ruby: Easiest Way to Filter Hash Keys?
...answer: Even though this is answer (as of the time of this comment) is the selected answer, the original version of this answer is outdated.
I'm adding an update here to help others avoid getting sidetracked by this answer like I did.
As the other answer mentions, Ruby >= 2.5 added the Hash#sli...
Pycharm: run only part of my Python file
... easier way.
go to File -> Settings -> Keymap
Search for Execute Selection in Console and reassign it to a new shortcut, like Crl + Enter.
This is the same shortcut to the same action in Spyder and R-Studio.
sha...
Recommended SQL database design for tags or tagging [closed]
...ries which you will do: Output all Tags for one Item, draw a Tag-Cloud and select all items for one Tag Title.
All Tags for one Item:
3-Table:
SELECT Tag.Title
FROM Tag
JOIN ItemTag ON Tag.TagID = ItemTag.TagID
WHERE ItemTag.ItemID = :id
2-Table:
SELECT Tag.Title
FROM Tag
WHERE Tag.Item...
select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
select、poll、epoll之间的区别总结[整理]select，poll，epoll都是IO多路复用的机制。I O多路复用就通过一种机制，可以监视多个描述符，一旦某个描述符就绪（一般是读就绪或者写就绪...select，poll，epoll都是IO多路复用的机制。I/O多路...