null값을 not null로 not null을 null로 바꾸기

	if (dataGridView2.Rows[0].Cells[2].Value.ToString().Trim() != dataGridView2.Rows[0].Cells[9].Value.ToString().Trim())
			{
				if(dataGridView2.Rows[0].Cells[2].Value.ToString().Trim() == "NO")
				{
					string alterTable = "ALTER TABLE " + tbl + " MODIFY `" + dataGridView2.Rows[0].Cells[7].Value.ToString() + "` " + dataGridView2.Rows[0].Cells[1].Value.ToString() not null;
					Create(alterTable);
				}
				else if(dataGridView2.Rows[0].Cells[2].Value.ToString().Trim() == "YES")
				{
					string alterTable = "ALTER TABLE " + tbl + " MODIFY `" + dataGridView2.Rows[0].Cells[7].Value.ToString() + "` " + dataGridView2.Rows[0].Cells[1].Value.ToString();
					Create(alterTable);
				}
			}

 

https://gocoder.tistory.com/2376

MySQL - 컬럼 not null 로 변경하기 / alter table