嵌套游标以生成复杂的报表

--以下示例显示如何嵌套游标以生成复杂的报表。为每个供应商声明内部游标
SET NOCOUNT ON
DECLARE @vendor_id int, @vendor_name nvarchar(50),
@message varchar(80), @product nvarchar(50)
PRINT '-------- Vendor Products Report --------'
DECLARE vendor_cursor CURSOR FOR
SELECT VendorID, Name
FROM Purchasing.Vendor
WHERE PreferredVendorStatus = 1
ORDER BY VendorID
OPEN vendor_cursor
FETCH NEXT FROM vendor_cursor
INTO @vendor_id, @vendor_name
WHILE @@FETCH_STATUS = 0
BEGIN
PRINT ' '
SELECT @message = '----- Products From Vendor: ' +
@vendor_name
PRINT @message
-- Declare an inner cursor based
-- on vendor_id from the outer cursor.
DECLARE product_cursor CURSOR FOR
SELECT v.Name
FROM Purchasing.ProductVendor pv, Production.Product v
WHERE pv.ProductID = v.ProductID AND
pv.VendorID = @vendor_id-- Variable value from the outer cursor
OPEN product_cursor
FETCH NEXT FROM product_cursor INTO @product
IF @@FETCH_STATUS <> 0
PRINT ' <<None>>'
WHILE @@FETCH_STATUS = 0
BEGIN
SELECT @message = ' ' + @product
PRINT @message
FETCH NEXT FROM product_cursor INTO @product
END
CLOSE product_cursor
DEALLOCATE product_cursor
-- Get the next vendor.
FETCH NEXT FROM vendor_cursor
INTO @vendor_id, @vendor_name
END
CLOSE vendor_cursor
DEALLOCATE vendor_cursor