Select 并计算有多少行

Question

Sorry, I'm just learning C#. I'm use to HTML/PHP then actual programming.

I'm looking to use SQL SELECT to view data from search result however it's likely that because of multiple LIKE it may bring multiple rows (which I want) however if it brings multiple rows instead of selecting the first row to display I want a IF message stating that there is more than one row matching the criteria. Below is my current code (I have removed some code from it after if (recordfound) to shorten the code for this question)

SqlConnection con1 = new SqlConnection(@Settings.Default.database);
con1.Open();
string qu = "SELECT * FROM addresses WHERE road LIKE '%" + inclocroad.Text.Trim() + "%' OR postcode LIKE '%" + inclocroad.Text.Trim() + "%' OR full_address LIKE '%" + inclocroad.Text.Trim() + "%' OR Property LIKE '%" + inclocno.Text.Trim() + "%' OR full_address2 LIKE '%" + inclocroad.Text.Trim() + "%' ";
SqlCommand cmd1 = new SqlCommand(qu, con1);
SqlDataReader dr = cmd1.ExecuteReader();
bool recordfound = dr.Read();
if (recordfound)
{
    //Displays data from row
} 
else
{
    messagebox.show("No data found");
}

Example

User clicks button

SQL uses SELECT QUERY where the user has written the search result

IF SELECT QUERY has more than 1 row then display message box

Otherwise show the only row matching the search result.

Answer 1

You can use this if you are hoping to load data using DataTable.

    SqlCommand cmd1 = new SqlCommand(qu, con1);
    SqlDataReader dr = cmd1.ExecuteReader();
    bool recordfound = dr.Read();

    DataTable dt = new DataTable();
    if (recordfound)
    {
         dt.Load(reader);
    } 
    
    int numRows= dt.Rows.Count;
    if(numRows > 1){
        messagebox.show("Data found"+ numRows);
    }
    else
    {
        messagebox.show("No data found");
    }

Answer 2

Well, why don't you just count them:

SELECT COUNT(1)... .

Since we are talking about just few rows it doesn't hurt performance or anything.

Answer 3

It's so simple... I just was having a moment.

I've made two SQL's with a IF query if it held more results or not. The first SQL being a COUNT using ExecuteScalar than using a IF statement if it did hold more than one record.

Thanks for the help.