SQL

Question

我有以下查询

SELECT VALUE
    ,Source1
    ,Source2
    ,DocNo
FROM myTable

它returns以下数据：

我想根据以下条件计算减法：

for DocNo A1
if(Source1=1 and Source2=0) VALUE 34
if(Source1=1 and Source2=0) VALUE 21
subtraction  two row 34 - 21 = 13

有什么想法吗？

预期结果：

Answer 1

如果我对你的问题理解正确，下面的查询就是你想要的：

SELECT Value, Score1, Score2, DocNo
FROM TestTable 
WHERE Score1 = 0

UNION 

SELECT MAX(Value) - MIN(Value) AS Value, 1, 1, DocNo
FROM TestTable 
WHERE Score1 = 1
GROUP BY DocNo
ORDER BY DocNo, Score1

DEMO 相同。

Answer 2

如果您使用的是 SQL Server 2012 或更高版本，您可以使用 LEAD() 函数。

WITH cte_1
AS
(SELECT VALUE, 
        VALUE-LEAD(VALUE) OVER(PARTITION BY DocNo ORDER BY DocNo) Result,
       Source1, 
       Source2,
       LEAD(Source1) OVER(PARTITION BY DocNo ORDER BY DocNo) NxtSource1,
       LEAD(Source2) OVER(PARTITION BY DocNo ORDER BY DocNo) NxtSource2,
       DocNo   
     FROM #myTable)
SELECT Case WHEN (Source1=1 AND NxtSource1=1) AND (Source2=0 AND NxtSource2=1) THEN Result ELSE VALUE END as Value,
       Source1,Source2,DocNo
FROM cte_1
WHERE (Source1<>1 OR source2 <>1)

输出：

SQL - 减法行

SQL - subtraction row

row

subtraction