order_id,date,category,units,unit_price_cents
O001,2026-04-01,notebooks,3,250
O002,2026-04-01,pens,10,80
O003,2026-04-02,notebooks,2,250
O004,2026-04-02,markers,4,150
O004,2026-04-02,markers,4,150
O005,2026-04-03,pens,,80
O006,2026-04-03,markers,-2,150
O007,2026-04-04,notebooks,1,unknown
O008,not-a-date,pens,5,80
O009,2026-04-04, PENS ,6,80
O010,2026-04-05,,2,150
O011,2026-04-05,notebooks,5,250
O012,2026-04-06,markers,3,150
O013,2026-04-06,pens,7,80
O014,2026-04-07,notebooks,4,250
O015,2026-04-07,markers,2,150
