instruction: A bar chart for what are the number of the invoice dates for customers with the first name Astrid and the last name Gruber?, order from low to high by the Y-axis.
response: SELECT InvoiceDate, COUNT(InvoiceDate) FROM Customer AS T1 JOIN Invoice AS T2 ON T1.CustomerId = T2.CustomerId WHERE T1.FirstName = "Astrid" AND LastName = "Gruber" ORDER BY COUNT(InvoiceDate)