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MySQL 按日期分组并统计截止当前时间的总数
建表语句
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
— —————————-
— Table structure for t_reg
— —————————-
DROP TABLE IF EXISTS `t_reg`;
CREATE TABLE `t_reg` (
`ID` int(11) NOT NULL AUTO_INCREMENT COMMENT ‘ID 编号 ’,
`REG_TIME` datetime(0) NULL DEFAULT NULL COMMENT ‘ 时间 ’,
`REG_COUNT` int(11) NULL DEFAULT NULL COMMENT ‘ 数量 ’,
PRIMARY KEY (`ID`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 8 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;
— —————————-
— Records of t_reg
— —————————-
INSERT INTO `t_reg` VALUES (1, ‘2019-05-01 08:08:12’, 1);
INSERT INTO `t_reg` VALUES (2, ‘2019-05-02 00:09:09’, 10);
INSERT INTO `t_reg` VALUES (3, ‘2019-05-02 13:08:08’, 2);
INSERT INTO `t_reg` VALUES (4, ‘2019-05-03 15:08:05’, 4);
INSERT INTO `t_reg` VALUES (5, ‘2019-05-03 17:08:08’, 6);
INSERT INTO `t_reg` VALUES (6, ‘2019-05-16 21:01:12’, 4);
INSERT INTO `t_reg` VALUES (7, ‘2019-05-03 05:08:09’, 11);
SET FOREIGN_KEY_CHECKS = 1;
表结构如下所示:REG_COUNT 表示当天新增的用户数
现在的需求是这样的:按每天分组,查询当天新增的用户总数和截止到当前时间新增的用户总数,结果如下:
SQL 语句如下:
SELECT
reg_time,
min_total AS ‘ 小计 ’,
@total := @total + min_total AS ‘ 总计 ’
FROM
(SELECT date( reg_time) AS reg_time,
sum(reg_count) AS min_total FROM t_reg GROUP BY date(reg_time) ) AS temp,
(SELECT @total := 0) AS T1
ORDER BY
reg_time;
解释一下:SELECT @total := 0,, 这句的意思是给临时变量 @total 设置值为 0;
如此即可得出上面的结果满足需求.
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