SQLite 3.27

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CREATE TABLE IF NOT EXISTS time_table (TIME1 TEXT, TIME2 TEXT);
✓
INSERT INTO time_table (TIME1,TIME2) VALUES 
 ('14:14:04.446258','14:14:04.446377'),
 ('14:13:27.742646','14:13:27.649184');
✓
select abs(CAST(
        (JulianDay(TIME1) - JulianDay(TIME2)) * 24 * 60 * 60 * 1000 * 1000 + 
        (substr(TIME1, -3) - substr(TIME2, -3))
        AS INTEGER
        )) diff_microsec 
from time_table;


diff_microsec


119

93481


select abs((strftime('%s', TIME1) - strftime('%s', TIME2)) * 1000 * 1000 + 
           (substr(TIME1, -6) - substr(TIME2, -6))
       ) diff_microsec 
from time_table;


diff_microsec


119

93462


select abs((strftime('%s', TIME1) - strftime('%s', TIME2)) * 1000 * 1000 + 
           (substr(TIME1, instr(TIME1, '.') + 1) - substr(TIME2, instr(TIME2, '.') + 1))
       ) diff_microsec 
from time_table;


diff_microsec


119

93462