如何在MySQL中聯合10個表？

Question

我必須使用union 10表執行很多查詢，如下所示。我一直在努力尋找一種有效的方式將它從order0循環到order9。有沒有人解決類似的問題？

select col1, col2 from order0 union all 
select col1, col2 from order1 union all 
select col1, col2 from order2 union all 
select col1, col2 from order3 union all 
select col1, col2 from order4 union all 
select col1, col2 from order5 union all 
select col1, col2 from order6 union all 
select col1, col2 from order7 union all 
select col1, col2 from order8 union all 
select col1, col2 from order9； 

Answer 1

您可以使用UNION語句創建視圖。這樣，您只需使用視圖名稱即可查看查詢中的所有訂單（例如，從訂單中選擇*）。

CREATE VIEW orders 
AS 
select col1, col2 from order0 union all 
select col1, col2 from order1 union all 
select col1, col2 from order2 union all 
select col1, col2 from order3 union all 
select col1, col2 from order4 union all 
select col1, col2 from order5 union all 
select col1, col2 from order6 union all 
select col1, col2 from order7 union all 
select col1, col2 from order8 union all 
select col1, col2 from order9；