Hello! There is a table
IdStudenta/IdSpravki/Nachalo/Konec/Primechanie . How can I calculate the number of days with the student's certificates, knowing the beginning and end of the certificate, while excluding weekends, or even better, for example, create a table "holidays" and enter data like 8.03.2012 = March 8, etc. and that these dates were excluded too. In general, I want to get an answer like:
idstudent/idspravki/Count 1/1/ 20
(for example, 1st student on 1st help 20 days pass).
And the option is more complicated: If there is an intersection of certificates, for example, one certificate 1.1.2012-20.1.2012 - note-Bronchitis, and another 12.1.2012-28.1.2012 note - participation in the conference and must be displayed in another form, for example
idstudenta/idspravki/date/primechanie 1/ 1/ 1.1.2012/Бронхит 1/ 1/ 2.1.2012/Бронхит ..... 1/ 1/ 12.1.2012/Бронхит 1/ 2/ 12.1.2012/УЧАСТИЕ В КОНФЕРЕНЦИИ ...
How to make a request to get such an answer?