sql - 表 2 の作業時間を比較して、表 1 の自由時間を見つける

Question

create table timetable( work_date date, tech_id int,
    block_1_firsthalf_start_time datetime,  block_1_end_time datetime,
    block_2_secondhalf_start_time datetime, block_2_end_time datetime,
    block_3_over_time datetime, block_3_over_end_time datetime,
    block_4_first_break_start_time datetime,    block_4_first_break_end_time datetime,
    block_5_second_break_start_time datetime,   block_5_second_break_end_time datetime)

insert into timetable values(
'8/6/2013', 1,
    '8/6/13 6:00 AM',   '8/6/13 10:00 AM',
    '8/6/13 11:00 AM',  '8/6/13 6:00 PM',
    '8/6/13 6:30 PM',   '8/6/13 8:00 PM'
    '8/6/13 7:00 AM',   '8/6/13 8:00 AM',
    '8/6/13 5:00 PM',   '8/6/13 5:30 PM')

別のテーブル:

create table jobtable(tech_id   int,Job_starting_time datetime, Job_end_time datetime)

insert into jobtable values(1,  '8/6/13 7:00 AM','8/6/13 8:00 AM')

次に、employee.pl 共有のために 1 日の自由時間を見つける必要があります。