如何找到最低值和相應的日期SQL-Server 2014

Question

我有示例數據， 請參見SQL Fiddle 。 我想從值列中找到最低值，並從上載日期列中找到最低值的日期。 我嘗試了以下查詢，但它無法正常工作並顯示所有值。

SELECT
    username,
    MIN(Value1) AS MinValue1,
    CASE 
        WHEN value1 = MIN(value1) THEN uploaded_date
    END
    AS MinDate
FROM
    test

GROUP BY
    username

Answer 1

您可以使用RANK窗口函數來找到每個用戶名的最小值：

SELECT username, value1, uploaded_date
FROM   (SELECT username, value1, uploaded_date,
               RANK() OVER (PARTITION BY username ORDER BY value1 ASC) AS rk
        FROM   test) t
WHERE  rk = 1

SQLFIddle

Answer 2

SELECT test. username,value1,MIN(uploaded_date  )FROM
(Select MIN(value1) MinValue1,username from test group by username ) A
INNER JOIN
test 
ON A.MinValue1 = test.Value1
AND A.username = test.username
GROUP BY
test. username,value1

您的查詢無效，因為您正在使用選擇列表中的列，因此Group by子句會將所有不同的值分組到每一行中

Answer 3

我希望這能幫到您

  ;with CTE as(
    SELECT username,
      MIN(Value1) AS MinValue1
  FROM
      test
  GROUP BY 
    username
  )

  select c.username,MinValue1,dt.uploaded_date from CTE c
  cross apply(select top 1 uploaded_date from test where value1=c.MinValue1 and username=c.username order by uploaded_date desc) dt

Answer 4

select Value1, update_date from test order by Value1 limit 1