大约有 44,000 项符合查询结果（耗时：0.0456秒） [XML]
What is the intent of the methods getItem and getItemId in the Android class BaseAdapter?
... ListView item, it's that simple. When the system notifies you of the user selection, you receive three identifying variables to tell you what was selected:
a reference to the view itself,
its numeric position in the list,
this long you attached to the individual elements.
It's up to you to deci...
Is there a good reason I see VARCHAR(255) used so often (as opposed to another length)?
...n multiple courses, books, and jobs, I have seen text fields defined as VARCHAR(255) as kind of the default for "shortish" text. Is there any good reason that a length of 255 is chosen so often, other than being a nice round number ? Is it a holdout from some time in the past when there was a goo...
How do I get SUM function in MySQL to return '0' if no values are found?
...
Use COALESCE to avoid that outcome.
SELECT COALESCE(SUM(column),0)
FROM table
WHERE ...
To see it in action, please see this sql fiddle: http://www.sqlfiddle.com/#!2/d1542/3/0
More Information:
Given three tables (one with all numbers, one with all nul...
How to map calculated properties with JPA and Hibernate
...e float finalPrice;
Or even complex queries on other tables:
@Formula("(select min(o.creation_date) from Orders o where o.customer_id = id)")
private Date firstOrderDate;
Where id is the id of the current entity.
The following blog post is worth the read: Hibernate Derived Properties - Perform...
Best way to get identity of inserted row?
...rator error', GETDATE());
--Display the result set of the table variable.
SELECT NewScrapReasonID, Name, ModifiedDate FROM @MyTableVar;
--Display the result set of the table.
SELECT ScrapReasonID, Name, ModifiedDate
FROM Production.ScrapReason;
GO
...
Select which href ends with some string
Is it possible using jQuery to select all <a> links which href ends with "ABC"?
5 Answers
...
SQL WITH clause example [duplicate]
...ngle sub-query alias.
WITH <alias_name> AS (sql_subquery_statement)
SELECT column_list FROM <alias_name>[,table_name]
[WHERE <join_condition>]
When using multiple sub-query aliases, the syntax is as follows.
WITH <alias_name_A> AS (sql_subquery_statement),
<alias_name_...
Toggle button using two image on different state
...k.xml in drawable folder
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- When selected, use grey -->
<item android:drawable="@drawable/selected_image"
android:state_checked="true" />
<...
Why is it impossible to build a compiler that can determine if a C++ function will change the value
... /* modify variable */
variable = 1;
}
}
int main(int argc, char **argv) {
if (modifies_variable(f, variable)) {
printf("Modifies variable\n");
} else {
printf("Does not modify variable\n");
}
return 0;
}
...
How to select all records from one table that do not exist in another table?
...
SELECT t1.name
FROM table1 t1
LEFT JOIN table2 t2 ON t2.name = t1.name
WHERE t2.name IS NULL
Q: What is happening here?
A: Conceptually, we select all rows from table1 and for each row we attempt to find a row in table2 wi...