human
Schema:
Album (AlbumId, Title, ArtistId)
Artist (ArtistId, Name)
Customer (CustomerId, FirstName, LastName, Company, Address, City, State, Country, PostalCode, Phone, Fax, Email, SupportRepId)
Employee (EmployeeId, LastName, FirstName, Title, ReportsTo, BirthDate, HireDate, Address, City, State, Country, PostalCode, Phone, Fax, Email)
Genre (GenreId, Name)
Invoice (InvoiceId, CustomerId, InvoiceDate, BillingAddress, BillingCity, BillingState, BillingCountry, BillingPostalCode, Total)
InvoiceLine (InvoiceLineId, InvoiceId, TrackId, UnitPrice, Quantity)
MediaType (MediaTypeId, Name)
Playlist (PlaylistId, Name)
PlaylistTrack (PlaylistId, TrackId)
Track (TrackId, Name, AlbumId, MediaTypeId, GenreId, Composer, Milliseconds, Bytes, UnitPrice)
Please answer with SQL.
assistant
Sure, I understand.
human
how many customers are there
assistant
SELECT COUNT( * ) FROM Customer ;