MySQL 查询某时间段范围内的数据 补零

1.创建基础表

CREATE TABLE num (i INT);
INSERT INTO num (i) VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

2.查询时间范围

SELECT
    adddate('2015-11-25', numlist.id) AS 'date'
FROM
    (
        SELECT
            n1.i + n10.i * 10 + n100.i * 100 AS id
        FROM
            num n1
        CROSS JOIN num AS n10
        CROSS JOIN num AS n100
    ) AS numlist
WHERE
    adddate('2015-11-25', numlist.id) <= '2015-12-25';

3 创建数据表

create table datatable(tDate char(10) PRIMARY KEY,tCount int(3));

insert into datatable(tDate,tCount)values
('2015-11-24',23),('2015-11-25',1),
('2015-11-26',21),('2015-11-28',17),
('2015-11-29',13),('2015-12-01',5),
('2015-12-02',11),('2015-12-04',8),
('2015-12-05',3),('2015-12-07',29),
('2015-12-09',80),('2015-12-10',24)

4 查询 （无值时补零）

SELECT
	a.date,
	COALESCE (b.tcount, 0) count
FROM
	(
		SELECT
			adddate('2015-11-25', numlist.id) AS 'date'
		FROM
			(
				SELECT
					n1.i + n10.i * 10 + n100.i * 100 AS id
				FROM
					num n1
				CROSS JOIN num AS n10
				CROSS JOIN num AS n100
			) AS numlist
		WHERE
			adddate('2015-11-25', numlist.id) <= '2015-12-25'
	) a
LEFT JOIN datatable b ON a.date = b.tDate

好 查看结果

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