sql - variable storage

What is the simplest way to store a string into variable. For example

How do I store something into @bleh variable.

SqlCommand stej = new SqlC开发者_运维知识库ommand("SELECT COUNT(*) FROM test3 WHERE PostID = @bleh", con);

@bleh variable has to be set somehow. I tried replacing @bleh with a 100,abc,da, etc. And it works. But my bleh variable will change with the loop.

Thanks

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These are called Parameters.

To set the value:

stej.Parameters.AddWithValue("@bleh", postId);

(There are more options, if you need to explicitly control the datatype, etc)

A single Parameter can only contain one value though. If you wish to pass multiple values, you would need multiple parameters.

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Use a sql parameter

 using ( SqlConnection conn = new SqlConnection( "connection string" )
    {
      conn.Open();

      string selstr = "SELECT COUNT(*) FROM test3 WHERE PostID = @bleh";
      SqlCommand cmd = new SqlCommand( selstr, conn );
      SqlParameter name = cmd.Parameters.Add( "@bleh", SqlDbType.NVarChar, 255 );
      name.Value = "value";
      int count = cmd.ExecuteScalar();
      //Do you stuff
   }