如何处理 T-SQL 中具有 "Union All" 但第二个 "Select" 始终出现在底部的查询？

Question

如何处理 T-SQL 中具有“联合所有”但第二个“Select”始终出现在底部的查询？我有以下 SQL...

select Policy.[Effective Date], Policy.[Policy #], CLIENT.[NAME], Policy.[Premium]
From Policy, Client 
Where Policy.[Effective Date] > '2000-11-11' AND Policy.[Policy Type] <> 'Quote' AND Client.[CLIENTID] = Policy.[CLIENTID] 

union all

select null, null, 'Totals', sum(Policy.[Premium])
From Policy, Client 
Where Policy.[Effective Date] > '2000-11-11' AND Policy.[Policy Type] <> 'Quote' AND Client. 
CLIENTID = Policy.CLIENTID
Order By CLIENT.NAME

但结果看起来像...

Answer 1

你需要额外添加一个固定的排序列。这通常是非常有效的，因为它通常使用Merge Concatenation，as explained by Paul White。

我建议您不要使用古老且已弃用的 , 连接语法。我还建议您不要使用需要引用的列名。

select Policy.[Effective Date], Policy.[Policy #], CLIENT.[NAME], Policy.[Premium], 1 AS ordering
From Policy
JOIN Client ON Client.[CLIENTID] = Policy.[CLIENTID] 
Where Policy.[Effective Date] > '2000-11-11' AND Policy.[Policy Type] <> 'Quote'

union all

select null, null, 'Totals', sum(Policy.[Premium]), 2
From Policy
JOIN Client ON Client.CLIENTID = Policy.CLIENTID
Where Policy.[Effective Date] > '2000-11-11' AND Policy.[Policy Type] <> 'Quote'
Order By Ordering, CLIENT.NAME

如果你不想ordering出现在结果中那么你需要子查询：

select [Effective Date], [Policy #], [NAME], [Premium]
FROM (
    select Policy.[Effective Date], Policy.[Policy #], CLIENT.[NAME], Policy.[Premium], 1 AS ordering
    From Policy
    JOIN Client ON Client.[CLIENTID] = Policy.[CLIENTID] 
    Where Policy.[Effective Date] > '2000-11-11' AND Policy.[Policy Type] <> 'Quote'

    union all

    select null, null, 'Totals', sum(Policy.[Premium]), 2
    From Policy
    JOIN Client ON Client.CLIENTID = Policy.CLIENTID
    Where Policy.[Effective Date] > '2000-11-11' AND Policy.[Policy Type] <> 'Quote'
)
Order By Ordering, CLIENT.NAME

分组集

我注意到您在这里所做的只是第一个结果的汇总。所以你实际上可以使用 GROUPING SETS syntax 来获得你想要的结果而无需额外的查询。它会更有效率：

select Policy.[Effective Date], Policy.[Policy #], ISNULL(CLIENT.[NAME], 'Totals') AS Name, SUM(Policy.[Premium])
From Policy
JOIN Client ON Client.[CLIENTID] = Policy.[CLIENTID] 
Where Policy.[Effective Date] > '2000-11-11' AND Policy.[Policy Type] <> 'Quote'
GROUP BY GROUPING SETS (
    (Policy.[Effective Date], Policy.[Policy #], CLIENT.[NAME], Policy.[Premium]),
    ()
)
ORDER BY
    GROUPING_ID(Policy.[Effective Date], Policy.[Policy #], CLIENT.[NAME], Policy.[Premium]),
    CLIENT.[NAME]

function GROUPING_ID returns 该行中聚合的每一列的 1 位，因此对于我们的总数，我们得到位 1111 排序在 0000 之后其余结果。

如何处理 T-SQL 中具有 "Union All" 但第二个 "Select" 始终出现在底部的查询？

How do I Process a Query in T-SQL that has a "Union All" but get the Second "Select" to always appear at the bottom?

sql

tsql

union-all

分组集