=====Kunden im Februar===== mysql> SELECT R_Kunde, COUNT(*) AS "Aufträge" FROM rechnungen WHERE R_Datum BETWEEN "2013-02-01" AND "2013-02-28" GROUP BY R_Kunde; +---------+-----------+ | R_Kunde | Aufträge | +---------+-----------+ | 1 | 3 | | 2 | 1 | +---------+-----------+ =====Alle Rechnungen mit Gesamtsumme von Kunde 1===== mysql> SELECT R.R_Nr, (RP.Stck*RP.Einzelpreis) AS Summe FROM rechnung_pos AS RP, rechnungen AS R WHERE RP.R_Nr = R.R_Nr AND R.R_Kunde = 1 AND R.R_Datum BETWEEN "2013-02-01" AND "2013-02-28"; +------+-------+ | R_Nr | Summe | +------+-------+ | 2 | 280 | | 3 | 100 | | 4 | 200 | +------+-------+ =====Gesamtgewinn durch Kunde 1===== mysql> SELECT SUM(RP.Stck*RP.Einzelpreis) AS Summe FROM rechnung_pos AS RP, rechnungen AS R WHERE RP.R_Nr = R.R_Nr AND R.R_Kunde = 1 AND R.R_Datum BETWEEN "2013-02-01" AND "2013-02-28"; +-------+ | Summe | +-------+ | 580 | +-------+ =====Meist genutzte Geräte===== mysql> SELECT RP.G_Nr, G.G_Bezeichnung, COUNT(*) AS "Ausgeliehen" FROM rechnung_pos AS RP, geraete as G WHERE RP.G_Nr = G.G_Nr GROUP BY RP.G_Nr ORDER BY 3 DESC; +------+----------------+-------------+ | G_Nr | G_Bezeichnung | Ausgeliehen | +------+----------------+-------------+ | 5 | Thinkpad T430s | 4 | | 1 | Thinkpad X61 | 1 | | 3 | Thinkpad T61p | 1 | +------+----------------+-------------+