~~~ /* Navicat MySQL Data Transfer Source Server : 本地數據庫 Source Server Version : 50553 Source Host : localhost:3306 Source Database : test Target Server Type : MYSQL Target Server Version : 50553 File Encoding : 65001 Date: 2018-02-07 16:39:54 */ SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for user -- ---------------------------- DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `id` int(11) NOT NULL, `name` varchar(255) NOT NULL, PRIMARY KEY (`id`,`name`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; -- ---------------------------- -- Records of user -- ---------------------------- INSERT INTO `user` VALUES ('1', 'a'); INSERT INTO `user` VALUES ('1', 'b'); INSERT INTO `user` VALUES ('1', 'c'); INSERT INTO `user` VALUES ('2', 'a'); INSERT INTO `user` VALUES ('2', 'b'); INSERT INTO `user` VALUES ('2', 'c'); INSERT INTO `user` VALUES ('3', 'a'); INSERT INTO `user` VALUES ('3', 'b'); INSERT INTO `user` VALUES ('3', 'c'); ~~~ 1. 分組統計： ~~~ SELECT COUNT(*) FROM `user` GROUP BY `id` ~~~  2. 分組統計匯總： ~~~ select count(t.counts) from (select id,count(*) counts from `user` group by id) t ~~~