小编Sal*_*lim的帖子

请考虑以下示例:

CREATE VIEW VW_YearlySales
AS

SELECT 2011 AS YearNo, ProductID, SUM(Amount) FROM InvoiceTable2011
UNION ALL
SELECT 2012 AS YearNo, ProductID, SUM(Amount) FROM InvoiceTable2012
UNION ALL
SELECT 2013 AS YearNo, ProductID, SUM(Amount) FROM InvoiceTable2013

GO

在InvoiceTable2013实际上并不存在并记录2013年第一发票时,我不想现在就创建它,它会自动创建.

谁能帮助我如何指定一个条件来验证表的存在UNION ALL？

非常感谢您的帮助.