大约有 44,000 项符合查询结果（耗时：0.0613秒） [XML]
SQL JOIN and different types of JOINs
... @KNU The w3fools should give credit from where they have taken the idea for the pictures. See A visualization of SQL joins by Jeff Atwood (yes, the one who co-authored SO) and the linked article by Ligaya Turmelle where Jeff got the idea and explanded it.
– ypercubeᵀᴹ
...
How to check which locks are held on a table
...o add to the other responses, sp_lock can also be used to dump full lock information on all running processes. The output can be overwhelming, but if you want to know exactly what is locked, it's a valuable one to run. I usually use it along with sp_who2 to quickly zero in on locking problems.
Th...
How to copy a row and insert in same table with a autoincrement field in MySQL?
... You could programatically get then names of the columns using INFORMATION_SCHEMA ... I wonder if you could do it as a sub-query and some string functions? Hmmm...
– Yzmir Ramirez
Feb 6 '12 at 6:35
...
Does the join order matter in SQL?
Disregarding performance, will I get the same result from query A and B below? How about C and D?
4 Answers
...
The JPA hashCode() / equals() dilemma
...A entities and which hashCode() / equals() implementation should be used for JPA entity classes. Most (if not all) of them depend on Hibernate, but I'd like to discuss them JPA-implementation-neutrally (I am using EclipseLink, by the way).
...
Select multiple records based on list of Id's with linq
...
You can use Contains() for that. It will feel a little backwards when you're really trying to produce an IN clause, but this should do it:
var userProfiles = _dataContext.UserProfile
.Where(t => idList.Contains(t...
Remove Identity from a column in a table
...move the entire column:
ALTER TABLE yourTable
DROP COLUMN yourCOlumn;
Information about ALTER TABLE here
If you need to keep the data, but remove the IDENTITY column, you will need to:
Create a new column
Transfer the data from the existing IDENTITY column to the new column
Drop the existing I...
Bundle ID Suffix? What is it?
I'm new to the iPhone submission process. Apple asks for the Bundle ID Suffix. What is this? Not sure what to put here and what the significance of it is.
...
How do you use the “WITH” clause in MySQL?
... what the WITH clause represents - they are interchangeable)
The request for the feature dates back to 2006.
As mentioned, you provided a poor example - there's no need to perform a subselect if you aren't altering the output of the columns in any way:
SELECT *
FROM ARTICLE t
JOIN USE...
Check if a dialog is displayed with Espresso
...e tests with the new android-test-kit (Espresso) . But I can't find any information on how to check if a dialog is displayed and perform some actions on it (like clicking the positive and negative buttons, e.t.c.). Note that a dialog may be also displayed by a WebView , not by the application it...