判断视图存不存在
IF EXISTS(SELECT 1 FROM sys.views WHERE name='View_ProductInStockBill') DROP VIEW View_ProductInStockBill
https://www.cnblogs.com/YyuTtian/p/4610953.html
IF EXISTS(SELECT 1 FROM sys.views WHERE name='View_ProductInStockBill') DROP VIEW View_ProductInStockBill
https://www.cnblogs.com/YyuTtian/p/4610953.html