SQL添加所有選擇語句

Question

我有一個選擇語句顯示公司列表。

SELECT distinct [Company] 
    FROM [Records] 

如何添加條目「ALL」作爲返回列表中的第一項？

Answer 1

使用union all和order by：

select company 
from ((select distinct company, 1 as ordering from records) 
     union all 
     (select 'ALL', 0) 
    ) t 
order by ordering; 

在實踐中，以下似乎工作：

select 'ALL' as company 
union all 
select distinct company from records; 

但是，SQL Server不保證這些按順序執行。在實踐中，我從來沒有發現這種說法不會把ALL放在第一位，但據我所知，並不能保證。

Answer 2

嘗試與UNION ALL

SELECT 'ALL' 
    UNION ALL 
    SELECT distinct [Company] 
     FROM [Records] 

Answer 3

SELECT 'ALL' 
UNION ALL 
SELECT distinct [Company] 
FROM [Records] 

Answer 4

您可以使用UNION ALL並添加順序爲：

SELECT [Company] FROM 
    (SELECT 'All' as [Company], 0 as RecordOrder 
    UNION ALL 
    SELECT distinct [Company], 1 as RecordOrder 
    FROM [Records]) X 
ORDER BY RecordOrder