C#: SQL Getting the Last row from a SqlDataReader?

Question

I needed to sort the dates in a table column and get the last row (i.e.: the latest date) from the reader. I tried the following:

using (SqlConnection con = new SqlConnection(conString))
{
   SqlCommand cmd = new SqlCommand("Select * From ActivityTable 
                                             ORDER BY CONVERT(DATE, Date) ASC", con);
   con.Open();
   SqlDataReader rdr = cmd.ExecuteReader();

   //I need to skip reading all the rows UNTIL the last row. I only need the last row
   while (rdr.Read())
   {
     locationOfPrevious = rdr["Location"].ToString();
     nodeid_previous = rdr["NodeID"].ToString();

   }
   rdr.Close();
}

I believe the query is right but I can't get the LAST row from the query results (that is the last date recorded according to the sort). What do yall suggest? Thanks folks :)

Sql Basics Tutorial - Order By

MethodMan
– MethodMan

2015-03-02 16:58:32 +00:00
Commented Mar 2, 2015 at 16:58 — MethodMan
– MethodMan, Commented Mar 2, 2015 at 16:58

NDJ · Accepted Answer · 2015-03-02 16:56:00Z

4

i'd suggest ordering by desc and taking the first row - more efficient

answered Mar 2, 2015 at 16:56

NDJ

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4 Comments

MWUser Over a year ago

Why didn't I think of that Lmao xD That was the best. Thanks man :P

MWUser Over a year ago

I get a 'IndexOutOfRange Exception" though

NDJ Over a year ago

check the fields "Location" and "NodeID" exist and are correctly spelled?

Michael McGriff Over a year ago

@MWUser edit what you changed your code to above so we can see why you would be getting that error.

Vimal CK · Accepted Answer · 2015-03-02 17:03:47Z

0

Use below query

Select Top 1 * From ActivityTable ORDER BY CONVERT(DATE, Date) DESC //SQL

you can use LIMIT keyword to generate the same output in MySQL

Select * From ActivityTable ORDER BY CONVERT(DATE, Date) DESC LIMIT 0,1 //MYSQL

edited Mar 2, 2015 at 17:03

answered Mar 2, 2015 at 16:56

Vimal CK

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2 Comments

eggyal Over a year ago

TOP is not valid MySQL syntax.

MethodMan Over a year ago

in MySql that would be equiv to the key word LIMIT

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