大约有 45,000 项符合查询结果（耗时：0.0350秒） [XML]
Setting the selected value on a Django forms.ChoiceField
...t hand, but this Q/A comes up for searches related to trying to assign the selected value to a ChoiceField.
If you have already called super().__init__ in your Form class, you should update the form.initial dictionary, not the field.initial property. If you study form.initial (e.g. print self.init...
Select a Dictionary with LINQ
I have used the "select" keyword and extension method to return an IEnumerable<T> with LINQ, but I have a need to return a generic Dictionary<T1, T2> and can't figure it out. The example I learned this from used something in a form similar to the following:
...
Entity Framework select distinct name
...
Using lambda expression..
var result = EFContext.TestAddresses.Select(m => m.Name).Distinct();
share
|
improve this answer
|
follow
|
...
How do I get the “id” after INSERT into MySQL database with Python?
...
Does not works with duplicated records using insert, select and where.
– e-info128
Oct 27 '18 at 19:20
add a comment
|
...
What is the best way to paginate results in SQL Server
... sake of this example, let's assume that the query you're dealing with is
SELECT * FROM Orders WHERE OrderDate >= '1980-01-01' ORDER BY OrderDate
In this case, you would determine the total number of results using:
SELECT COUNT(*) FROM Orders WHERE OrderDate >= '1980-01-01'
...which may ...
SQL order string as number
...u can't do that then cast your column value to an integer explicitly with
select col from yourtable
order by cast(col as unsigned)
or implicitly for instance with a mathematical operation which forces a conversion to number
select col from yourtable
order by col + 0
BTW MySQL converts strings...
How to save MySQL query output to excel or .txt file? [duplicate]
...SV file:
MySQL provides an easy mechanism for writing the results of a select
statement into a text file on the server. Using extended options of
the INTO OUTFILE nomenclature, it is possible to create a comma
separated value (CSV) which can be imported into a spreadsheet
application suc...
Counting DISTINCT over multiple columns
... function turns the ints into varchars to make the distinct more reliable
SELECT COUNT(DISTINCT (CHECKSUM(DocumentId,DocumentSessionId)) + CHECKSUM(REVERSE(DocumentId),REVERSE(DocumentSessionId)) )
FROM DocumentOutPutItems
...
Is It Possible to NSLog C Structs (Like CGRect or CGPoint)?
...e-C data item. It can hold any of the scalar types such as int, float, and char, as well as pointers, structures, and object ids.
Example:
CGPoint cgPoint = CGPointMake(10,30);
NSLog(@"%@",[NSValue valueWithCGPoint:cgPoint]);
OUTPUT : NSPoint: {10, 30}
Hope it helps you.
...
What columns generally make good indexes?
...earching the results speedily from tables. So it is most important step to select which columns to be indexed. There are two major places where we can consider indexing: columns referenced in the WHERE clause and columns used in JOIN clauses. In short, such columns should be indexed against which yo...