在C＃中的DataTable上调用SQL System函数

Question

I need to execute the sql server system function over DataTable.

DataTable has a string value eg "12345", in this i need a substring which is configured in Sql server table like SUBSTRING(,0,2).

I'm able to get the condition from DB table. But how to apply this condition in DataTable?

Answer 1

There are many ways of achieving this.

1 - You can create a view that calls your function, ie:

Create View testView
As
Select
dbo.myFunction(parameter)
FROM dbo.TableName

2 - You can use C# Substring function as Ross mentioned in his comment:

DataTableString.Substring(0, 2)

Answer 2

You can use the SUBSTRING function in the query that is used to populate the DataTable . SUBSTRING(0, 2) was used in your question, I'm guessing you want the first two letters letters of the column? SUBSTRING in SQL Server starts at 1, while this same function begins at 0 in C#. You'll need to use (Column, 1, 2) in a SQL query to return the first two characters.

string connStr = @"YourConnectionString;";
string cmd = @"SELECT SUBSTRING(ColumnA, 1, 2) AS ColumnA from YourSchema.YourTable";
using (SqlConnection conn = new SqlConnection(connStr))
{
    conn.Open();
    DataTable dt = new DataTable();
    //create data adapter from string with SQL command and SQL Connection object
    SqlDataAdapter da = new SqlDataAdapter(cmd, conn);

    //populate DataTable
    da.Fill(dt);
}