创建操作 –> http://www.hangge.com/blog/cache/detail_1922.html 变换操作 –> http://www.hangge.com/blog/cache/detail_1932.html 过滤操作 –> http://www.hangge.com/blog/cache/detail_1933.html 组合操作 –> http://www.hangge.com/blog/cache/detail_1930.html 错误处理 –> http://www.hangge.com/blog/cache/detail_1936.html 辅助操作 –> http://www.hangge.com/blog/cache/detail_1950.html 条件和布尔操作 –> http://www.hangge.com/blog/cache/detail_1948.html 算术和聚合操作 –> http://www.hangge.com/blog/cache/detail_1934.html 连接操作 –> http://www.hangge.com/blog/cache/detail_1935.html