選擇在最早的記錄中的所有行

Question

我有一個名爲命令中─

表這給了我剛纔的1列 -

select min(OrderDate) from "order" 

不過我想查看該記錄的所有列。

讚賞任何幫助，

感謝

Answer 1

SELECT * 
from [order] 
WHERE OrderDate = (SELECT min(OrderDate) from [order]) 

Answer 2

使用order by沙top：

select top 1 o.* 
from orders o 
order by orderdate asc; 

編輯：

如果你想重複使用with ties：

select top 1 with ties o.* 
from orders o 
order by orderdate asc; 

Answer 3

雖然M. Ali's answer是準確的，但根據表的大小和索引配置，可能會導致性能下降。它需要兩次讀取表格。

在SQL Server 2005及更高版本上，可以使用窗口函數並將計劃限制爲通過表單讀取。對於非常小的數據集，查詢成本實際上更高，但讀取次數減半。對於大型數據集，這應該會導致顯着優異的性能。

代碼示例：

SET NOCOUNT ON; 

-- Populate Test Data 

DECLARE @Orders TABLE (OrderNum int IDENTITY, OrderDate datetime); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-04'); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-04'); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-04'); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-05'); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-05'); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-06'); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-07'); 
INSERT INTO @Orders (OrderDate) VALUES ('2015-04-07'); 

-- Run Tests 

SET STATISTICS IO ON; 

PRINT 'Full Table'; 
SELECT * FROM @Orders; 

PRINT 'Results using MIN'; 
SELECT  * 
FROM  @Orders 
WHERE  OrderDate = (SELECT min(OrderDate) FROM @Orders); 

PRINT 'Results using RANK'; 
WITH BaseData AS 
(
    SELECT 
     *, 
     RANK() OVER (ORDER BY OrderDate) AS OrderDateRank 
    FROM  @Orders 
) 
SELECT  * 
FROM  BaseData 
WHERE  OrderDateRank = 1; 

SET STATISTICS IO OFF; 

SET NOCOUNT OFF; 

查詢費用：

MIN： 0.0065718

RANK： 0.014645

統計：

Full Table 
Table '#1E0C7C2B'. Scan count 1, logical reads 1, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. 
Results using MIN 
Table '#1E0C7C2B'. Scan count 2, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. 
Results using RANK 
Table '#1E0C7C2B'. Scan count 1, logical reads 1, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.