MySQL 8.0

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CREATE TABLE timetable (
id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
project_id INT(6) NOT NULL,
item VARCHAR(35) NOT NULL,
quantity INT(3) ZEROFILL NOT NULL,
dt_start DATETIME,
dt_END DATETIME
);

INSERT INTO timetable (project_id,item,quantity,dt_start,dt_end)
VALUES
(1234, 'table', 50, '2021-01-10 10:00:00', '2021-01-12 10:00:00'),
(1234, 'chair', 200, '2021-01-10 10:00:00', '2021-01-12 10:00:00'),
(1234, 'light', 2, '2021-01-10 10:00:00', '2021-01-12 10:00:00'),
(5678, 'table', 25, '2021-01-12 10:00:00', '2021-01-15 10:00:00'),
(5678, 'light', 3, '2021-01-12 10:00:00', '2021-01-15 10:00:00'),
(9876, 'table', 10, '2021-01-10 10:00:00', '2021-01-14 10:00:00'),
(9876, 'chair', 100, '2021-01-10 10:00:00', '2021-01-14 10:00:00'),
(2323, 'light', 10, '2021-01-12 10:00:00', '2021-01-15 10:00:00');

CREATE TABLE calendar (dt date not null primary key);
INSERT INTO calendar (dt)
VALUES ('2021-01-9'),('2021-01-10'),('2021-01-11'),('2021-01-12'),
('2021-01-13'),('2021-01-14'),('2021-01-15'),('2021-01-16'),
('2021-01-17'),('2021-01-18'),('2021-01-19'),('2021-01-20');

Records: 8  Duplicates: 0  Warnings: 0

Records: 12  Duplicates: 0  Warnings: 0

id	project_id	item	quantity	dt_start	dt_END	itm_sum
4	5678	table	025	2021-01-12 10:00:00	2021-01-15 10:00:00	35
5	5678	light	003	2021-01-12 10:00:00	2021-01-15 10:00:00	13
6	9876	table	010	2021-01-10 10:00:00	2021-01-14 10:00:00	35
7	9876	chair	100	2021-01-10 10:00:00	2021-01-14 10:00:00	100
8	2323	light	010	2021-01-12 10:00:00	2021-01-15 10:00:00	13