ID, date, problem-code
A44, 2016-12-09, P809
A44, 2016-12-09, P810
...
A99, 2016-12-09, P809
A99, 2016-12-09, P810

ID, date, problem-code
A44, 2016-12-09, [P809, P810]
...
A99, 2016-12-09, P809
A99, 2016-12-09, P810

ID, date, problem-code, call-number
A44, 2016-12-09, P809, 73
A44, 2016-12-09, P810, 73
...
A99, 2016-12-09, P809, 97
A99, 2016-12-09, P810, 98