Convert DateTime to a different format in sql - asp.net

Question

How can I convert/cast this datetime format: 06/17/2012 12:00:00 AM
To this date format : 2012/06/17
in a SQL Update Statement?
I need to change to fields. BeginDate, and EndDate. Both DateTime Types.
This is my Update statement so far:
Update discount set DiscountPromotionalID = #DiscountPromotionalID,
isActive =#isActive, Title = #Title, BeginDate = #BeginDate, EndDate = #EndDate,
DiscountPercentage = #DiscountPercentage
where DiscountPromotionalID = #DiscountPromotionalID;"

Answer 1

If you're storing it as NVARCHAR (which you shouldn't be) you can use the following to convert it when your doing your insert/update statement. I would recommend converting this column to a proper DateTime field then you can format as you wish within the presentation layer as commentors have suggested.
Checkout this resource for all your SQL Data Formatting needs (with example sql!)
http://www.sql-server-helper.com/tips/date-formats.aspx
I believe you're looking for something like this (from the resource above):
CONVERT(VARCHAR(10), GETDATE(), 111) AS [YYYY/MM/DD]

Answer 2

Like a C# DateTime value, a SQL Server DateTime value has no format: it's just a 64-bit field consisting of two 32-bit integers. The first counts days since the epoch (1 January 1900 00:00:00.000); the second counts time since start of day in 1/300ths of a second.
You apply formatting when you display it or convert it to char/varchar, either in SQL using CONVERT(), or in the client code.
Your update statement doesn't care about format: it cares about value. If you pass a C# DateTime value as a SqlParameter to your stored procedure or parameterized query, the Right Thing will happen: the CLR will magically translate the one into the other for you.
If, you pass a string as the DateTime parameter from C#, it needs to be in a format that SQL Server will recognize as a DateTime string. Assuming that's the case, the conversion from C# string to SQL Server DateTime value will likewise happen magically.
Given your update statement, code something like the following ought to do you:
public int UpdateDiscount( int discountPromotionalID , bool isActive , string title , DateTime beginDate , DateTime endDate , int discountPercentage )
{
const string updateQuery = #"
Update discount
set DiscountPromotionalID = #DiscountPromotionalID ,
isActive = #isActive ,
Title = #Title ,
BeginDate = #BeginDate ,
EndDate = #EndDate ,
DiscountPercentage = #DiscountPercentage
where DiscountPromotionalID = #DiscountPromotionalID
" ;
int rowsAffected ;
using ( SqlConnection connection = new SqlConnection( SomeConnectString ) )
using ( SqlCommand cmd = connection.CreateCommand() )
{
cmd.CommandText = updateQuery ;
cmd.CommandType = CommandType.Text ;
cmd.Parameters.AddWithValue( "#DiscountPromotionalID" , discountPromotionalID ) ;
cmd.Parameters.AddWithValue( "#isActive" , isActive ? 1 : 0 ) ; // C# bools are true/false; SQL bools are 1/0
cmd.Parameters.AddWithValue( "#Title" , title ) ;
cmd.Parameters.AddWithValue( "#BeginDate" , beginDate ) ;
cmd.Parameters.AddWithValue( "#EndDate" , endDate ) ;
cmd.Parameters.AddWithValue( "#DiscountPercentage" , discountPercentage ) ;
connection.Open() ;
rowsAffected = cmd.ExecuteNonQuery() ;
connection.Close() ;
}
return rowsAffected ;
}