大约有 41,000 项符合查询结果（耗时：0.0782秒） [XML]
Proper use of 'yield return'
...ng when one filter the stream (with where), or eventually process it (with select not being select(o => o)).
– Soleil - Mathieu Prévot
Sep 14 at 13:06
add a comment
...
Django ManyToMany filter()
...d it.
the above code will end up generating SQL that looks something like:
SELECT * FROM users WHERE id IN (SELECT user_id FROM userzones WHERE zone_id IN (1,2,3))
which is nice because it doesn't have any intermediate joins that could cause duplicate users to be returned
...
mysql check collation of a table
...ry INFORMATION_SCHEMA.TABLES and get the collation for a specific table:
SELECT TABLE_SCHEMA
, TABLE_NAME
, TABLE_COLLATION
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME = 't_name';
that gives a much more readable output in contrast to SHOW TABLE STATUS that contains a lot of irreleva...
400 BAD request HTTP error code meaning?
...
Selecting a HTTP response code is quite an easy task and can be described by simple rules. The only tricky part which is often forgotten is paragraph 6.5 from RFC 7231:
Except when responding to a HEAD request, the server...
Commit changes to a different branch than the currently checked out branch with subversion
... It must not be the root of the repository, less to duplicate in that way;
Select TortoiseSVN -> "Branch/tag...";
Set To URL: "svn://host/repository/FooBar/branches/FooBarBranchName";
Make sure [*] Working copy is selected. This will ensure the changes are commited;
Log message: "Experimenting wi...
How to replace a single word under cursor?
...22.333)? It looks like vim interprets / and . as end of the word and won't select the entire string.
– Alexander Cska
May 1 at 21:47
...
Get the first item from an iterable that matches a condition
...
Since this is the selected answer, I feel compelled to share an answer to selecting the first element correctly here. In short: usage of next shouldn't be encouraged.
– guyarad
Jul 7 '16 at 10:56
...
Accessing the index in 'for' loops?
...g enumerate, I switched to this approach to avoid having to write logic to select which object to enumerate.
– adg
Mar 31 '17 at 23:18
1
...
Increment a database field by 1
...complex depending on your specific needs:
INSERT into mytable (logins)
SELECT max(logins) + 1
FROM mytable
share
|
improve this answer
|
follow
|
...
Why do people hate SQL cursors so much? [closed]
...arts of the RDBMS work under the hood. Often CREATE TABLE and INSERT have SELECT statements, and the implementation is the obvious internal cursor implementation.
Using higher-level "set-based operators" bundles the cursor results into a single result set, meaning less API back-and-forth.
Cursor...