USE NORTHWND; SELECT DISTINCT Country FROM dbo.Customers; --Viết câu lệnh SQL lấy ra tên các mã số bưu điện khác nhau từ bảng nhà cung cấp -Suppliers SELECT DISTINCT PostalCode FROM Suppliers; --Viết ...

Group by ACCOUNT, then by date, process each group in turn, get the interval from first group from to the current group, and perform deduplication and counting. But SQL grouping must be accompanied by ...

Under the object explorer in SQL it's showing me about 5-10 columns but they all say "non-unique, non-clustered". When I go into design view of the table > indexes it shows me about 8-10 fields ...

A SELECT group of programmers with a DISTINCT advantage If you’re still with us, congratulate yourself—you survived the second part of our series on SQL basics!