T-SQL：选择趋势在两个时间段下降的帖子

我希望避免在表上进行子选择，以比较两个时期以及趋势是否下降

此选择获取一个期间的百分比

SELECT user, (SUM(value1)/SUM(value2)) AS percentage1
FROM table
WHERE (date BETWEEN @start1 AND @end1)
GROUP BY user
ORDER BY 2

这个查询得到了我想要的结果，但效率不是很高，因为有超过1亿行

SELECT t1.user, (SUM(t1.value1)/SUM(t1.value2)) AS percentage1,
(SELECT (SUM(t2.value1)/SUM(t2.value2)) AS percentage2
FROM table AS t2
WHERE t2.userID = t1.userID
AND (t2.date BETWEEN @start2 AND @end2)
)
FROM table AS t1
WHERE (t1.date BETWEEN @start1 AND @end1)
AND (SUM(t1.value1)/SUM(t1.value2)) < (SELECT (SUM(t2.value1)/SUM(t2.value2))
FROM table AS t2
WHERE t2.userID = t1.userID
AND (t2.date BETWEEN @start2 AND @end2)
)
GROUP BY t1.user

排除这样的行，因为趋势百分比较低

Bill, 24%, 18%
Nina, 84%, 56%

SQL Server 2016 Enterprise是数据库。

您可以试试这个

SELECT G1.user, G1.percentage1, G2.percentage2 
FROM 
    ( SELECT t1.user, t1.userID
        (SUM(t1.value1)/SUM(t1.value2)) AS percentage1,
      FROM table AS t1
      WHERE 
        (t1.date BETWEEN @start1 AND @end1)
      GROUP BY t1.user, t1.userID
    ) AS G1
    INNER JOIN (
        SELECT t2.userID, (SUM(t2.value1)/SUM(t2.value2)) AS percentage2
        FROM table AS t2
        WHERE 
            (t2.date BETWEEN @start2 AND @end2)
        GROUP BY t2.userID
    ) AS G2 ON G1.userID = G2.userID
WHERE 
    G1.percentage1 < G2.percentage2

DECLARE @start DATE
DECLARE @end DATE

SET @start = CASE WHEN @start1 < @start2 THEN @start1 ELSE @start2 END
SET @end = CASE WHEN @end1 > @end2 THEN @end1 ELSE @end2 END

SELECT * FROM (
    SELECT t.userID, 
        SUM( CASE WHEN t.date BETWEEN @start1 AND @end1 THEN t.value1 END ) / SUM( CASE WHEN t.date BETWEEN @start1 AND @end1 THEN t.value2 END ) AS percentage1, 
        SUM( CASE WHEN t.date BETWEEN @start2 AND @end2 THEN t.value1 END ) / SUM( CASE WHEN t.date BETWEEN @start2 AND @end2 THEN t.value2 END ) AS percentage2, 
    FROM table AS t
    WHERE 
        (t.date BETWEEN @start AND @end)
    GROUP BY t.userID
) AS SQ WHERE percentage1 < percentage2

但是如果您只想使用表中的一个select，那么您也可以尝试此方法

SELECT G1.user, G1.percentage1, G2.percentage2 
FROM 
    ( SELECT t1.user, t1.userID
        (SUM(t1.value1)/SUM(t1.value2)) AS percentage1,
      FROM table AS t1
      WHERE 
        (t1.date BETWEEN @start1 AND @end1)
      GROUP BY t1.user, t1.userID
    ) AS G1
    INNER JOIN (
        SELECT t2.userID, (SUM(t2.value1)/SUM(t2.value2)) AS percentage2
        FROM table AS t2
        WHERE 
            (t2.date BETWEEN @start2 AND @end2)
        GROUP BY t2.userID
    ) AS G2 ON G1.userID = G2.userID
WHERE 
    G1.percentage1 < G2.percentage2

DECLARE @start DATE
DECLARE @end DATE

SET @start = CASE WHEN @start1 < @start2 THEN @start1 ELSE @start2 END
SET @end = CASE WHEN @end1 > @end2 THEN @end1 ELSE @end2 END

SELECT * FROM (
    SELECT t.userID, 
        SUM( CASE WHEN t.date BETWEEN @start1 AND @end1 THEN t.value1 END ) / SUM( CASE WHEN t.date BETWEEN @start1 AND @end1 THEN t.value2 END ) AS percentage1, 
        SUM( CASE WHEN t.date BETWEEN @start2 AND @end2 THEN t.value1 END ) / SUM( CASE WHEN t.date BETWEEN @start2 AND @end2 THEN t.value2 END ) AS percentage2, 
    FROM table AS t
    WHERE 
        (t.date BETWEEN @start AND @end)
    GROUP BY t.userID
) AS SQ WHERE percentage1 < percentage2

---

我们可以尝试使用CTE方法，提供更高的可读性和灵活性，以便将来需要时进行修改。我在RequiredDate列中添加了索引以提高性能。希望能有帮助

IF OBJECT_ID('dbo.InputUsers') IS NULL
BEGIN
CREATE TABLE dbo.InputUsers (
UserNameID INT NOT NULL,
UserName NVARCHAR(MAX),
RequiredDate DATETIME,
Value1 DECIMAL,
Value2 DECIMAL
)
CREATE NONCLUSTERED INDEX IX_Users_RequiredDate   
    ON dbo.InputUsers (RequiredDate);   
END

DECLARE @Start1 NVARCHAR(20), @End1 NVARCHAR(20), @Start2 NVARCHAR(20), @End2 NVARCHAR(20)
SET @Start1 = '2018-05-26'
SET @End1 = '2018-05-27'

SET @Start2 = '2018-05-28'
SET @End2 = '2018-05-29'

INSERT INTO InputUsers(UserNameID, UserName, RequiredDate, Value1, Value2) VALUES
(1, 'Adam', '2018-05-29', 13, 25),
(1, 'Adam', '2018-05-28', 12, 25),
(1, 'Adam', '2018-05-27', 11, 25),
(1, 'Adam', '2018-05-26', 10, 25),

(2, 'Lisa', '2018-05-29', 19, 25),
(2, 'Lisa', '2018-05-28', 18, 25),
(2, 'Lisa', '2018-05-27', 17, 25),
(2, 'Lisa', '2018-05-26', 16, 25),

(3, 'John', '2018-05-29', 16, 25),
(3, 'John', '2018-05-28', 17, 25),
(3, 'John', '2018-05-27', 18, 25),
(3, 'John', '2018-05-26', 19, 25),

(4, 'Bill', '2018-05-29', 10, 25),
(4, 'Bill', '2018-05-28', 11, 25),
(4, 'Bill', '2018-05-27', 12, 25),
(4, 'Bill', '2018-05-26', 13, 25)

;WITH PercentageValues1 AS (SELECT UserNameID, UserName, SUM(Value1)*100 / SUM(Value2) AS Percentage
FROM dbo.InputUsers
WHERE RequiredDate >= @Start1 AND RequiredDate <= @End1
GROUP BY UserNameID, UserName
),
PercentageValues2 AS (SELECT UserNameID, UserName, SUM(Value1)*100 / SUM(Value2) AS Percentage
FROM dbo.InputUsers
WHERE RequiredDate >= @Start2 AND RequiredDate <= @End2
GROUP BY UserNameID, UserName
)
SELECT pv2.UserName, pv1.Percentage, pv2.Percentage
FROM PercentageValues2 pv2
LEFT JOIN PercentageValues1 pv1 ON 
pv2.UserNameID = pv1.UserNameID
WHERE pv2.Percentage > pv1.Percentage

---

示例数据将非常有用，它定义了所有变量的作用，并为我们设置了一个模式。您没有提供要计算的全部信息或数据集。这是两个select语句，这正是我想要避免的。我添加了一个select版本。使用单个select语句可能会遇到挑战。也许可以试试上面的代码，让我知道性能。