1 //假装using Dapper;
public IEnumerable<Books> GetBooks(int pageIndex, int pageSize)
{
    var conn = GetSqlConnection();
    
    var sql = "select * from books";
    var pagingSql = (sql , " id desc ", pageIndex, pageSize);
    var rowCount = conn.ExecuteScalar<int>($"select count(*) from ({sql}) x");
    var pagedList = conn.Query<Books>(pagingSql);
}

public SqlConnection GetSqlConnection()
{
    //假装返回一个connection对象
    return conn;
}

public string PagingSql(string sql, string orderby, int page, int pagesize)
{
    if (page <= 0)
    {
        page = 0;
    }
    else
    {
        page--;
    }

    var offset = page * pagesize;

    var _sql = $@"SELECT x.* from (
                {sql}
            ) x
            ORDER BY {orderby} 
            OFFSET {offset} ROW
            FETCH NEXT {(pagesize)} ROW ONLY";

    return _sql;
}