sql语句统计查询

/*
 Navicat Premium Data Transfer

 Source Server         : 127.0.0.1 - root
 Source Server Type    : MySQL
 Source Server Version : 80017
 Source Host           : 127.0.0.1:3306
 Source Schema         : mydb

 Target Server Type    : MySQL
 Target Server Version : 80017
 File Encoding         : 65001

 Date: 04/08/2021 15:32:57
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for crown
-- ----------------------------
DROP TABLE IF EXISTS `crown`;
CREATE TABLE `crown`  (
  `id` int(8) NOT NULL AUTO_INCREMENT,
  `team` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `years` int(8) NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of crown
-- ----------------------------
INSERT INTO `crown` VALUES (3, '活塞', 1990);
INSERT INTO `crown` VALUES (4, '公牛', 1991);
INSERT INTO `crown` VALUES (5, '公牛', 1992);
INSERT INTO `crown` VALUES (6, '公牛', 1993);
INSERT INTO `crown` VALUES (7, '火箭', 1994);
INSERT INTO `crown` VALUES (8, '火箭', 1995);
INSERT INTO `crown` VALUES (9, '公牛', 1996);
INSERT INTO `crown` VALUES (10, '公牛', 1997);
INSERT INTO `crown` VALUES (11, '公牛', 1998);
INSERT INTO `crown` VALUES (12, '马刺', 1999);
INSERT INTO `crown` VALUES (13, '湖人', 2000);
INSERT INTO `crown` VALUES (14, '湖人', 2001);
INSERT INTO `crown` VALUES (15, '湖人', 2002);
INSERT INTO `crown` VALUES (16, '马刺', 2003);
INSERT INTO `crown` VALUES (17, '活塞', 2004);
INSERT INTO `crown` VALUES (18, '马刺', 2005);
INSERT INTO `crown` VALUES (19, '热火', 2006);
INSERT INTO `crown` VALUES (20, '马刺', 2007);
INSERT INTO `crown` VALUES (21, '凯尔特人', 2008);
INSERT INTO `crown` VALUES (22, '湖人', 2009);
INSERT INTO `crown` VALUES (23, '湖人', 2010);

SET FOREIGN_KEY_CHECKS = 1;

SELECT
  r.team,
  MIN(y1),
  MAX(y2)
FROM
  (SELECT
    c1.`team`,
    c1.years AS y1,
    c2.`years` AS y2,
    c2.`years` - (@rowNum := @rowNum + 1) AS rownumflag
  FROM
    crown c1,
    crown c2,
    (SELECT
      (@rowNum := 0)) b
  WHERE c1.`years` + 1 = c2.`years`
    AND c1.`team` = c2.`team`) r
GROUP BY r.team,
  r.rownumflag