sql - How to write query to retrieve all columns and distinct for one column? -

I am writing to retrieve data from a database in a spreadsheet when I type c # I am using this to show the error for the query ( SqlCommand ) and one column to get all the columns that

the column 'date' Can not be set to empty Please use DBNull instead.

This is my query:

  Separately select the column name from the Tablename   
 I am missing On the other hand, while working back (an Excel table category => C #) we got it? Help me get it?  
  
 
 
 Perhaps your problem is behind this problem - Datatelle (and SpreadsheetGear API) you want to fill the first row with column heading information and then want to populate the data in the later rows.