Suppose we want to select the data from the database then we write the query for that .
Example:
SqlConnection con=new SqlConnection(Connetion name)
string selectPkId = @"SELECT PK_ID FROM TABLE"
SqlCommand cmd=new SqlCommand(selectPkId ,con);
So,my question is that why we basically use @ before the sql query.If I don't use @ before that then it again work fine (does not give any error), then what is need of using "@" ? Please tell me.
It's a verbatim string. This means newlines are preserved and escape sequences ignored:
string a = "hello, world"; // hello, world
string b = @"hello, world"; // hello, world
string c = "hello \t world"; // hello world
string d = @"hello \t world"; // hello \t world
string e = "Joe said \"Hello\" to me"; // Joe said "Hello" to me
string f = @"Joe said ""Hello"" to me"; // Joe said "Hello" to me
string g = "\\\\server\\share\\file.txt"; // \\server\share\file.txt
string h = @"\\server\share\file.txt"; // \\server\share\file.txt
MSDN Reference: String Literals
This comes in handy when you want escape sequences to be preserved without having to double escape them, eg:
string sql = @"UPDATE table SET comment='Hello\nWorld'"
// equivalent to:
string sql = "UPDATE table SET comment='Hello\\nWorld'"
Of course this is a very simple example, but most of the times it will give you a more readable string.