sql-server - 在 SQL 减法查询中将 varchar 转换为数字时出错

Question

我有这个查询

select SUM(quantity) from Sales join Document on Sales.IdDocument = Document.IdDocument where (IdTipoDocumento = 'vco' or IdTipoDocumento = 'vcr') and IdArticulo = '01-00321' and IdListaEmpresa = 1000129
-
(select SUM(quantity) from Sales join Document on Sales.IdDocument = Document.IdDocument where IdTipoDocumento = 'dco'  and IdArticulo = '01-00321' and IdListaEmpresa = 1000129)

如果我分别运行每一行，则每个查询都可以正常工作（第一个查询结果为 419，第二个查询结果为 380），但如果我尝试运行整个查询以获得结果（419-380），它会告诉我“转换数据类型时出错varchar 到数字。”

他们都应该已经是数字（数量字段无论如何都是整数类型）所以我不知道为什么会出现错误......

Answer 1

方法一：

SELECT
(select SUM(quantity) from Sales join Document on Sales.IdDocument = Document.IdDocument 
where (IdTipoDocumento = 'vco' or IdTipoDocumento = 'vcr') and IdArticulo = '01-00321' and 
IdListaEmpresa = 1000129)

-
(select SUM(quantity) from Sales join Document on Sales.IdDocument = Document.IdDocument 
where IdTipoDocumento = 'dco'  and IdArticulo = '01-00321' and IdListaEmpresa = 1000129)

方法二：

SELECT SUM(SQ)
FROM (
SELECT CASE WHEN (IdTipoDocumento = 'vco' or IdTipoDocumento = 'vcr') THEN SUM(Quantity)
WHEN IdTipoDocumento = 'dco' THEN -1*SUM(Quantity)
END AS SQ
FROM  Sales join Document on Sales.IdDocument = Document.IdDocument 
where (IdTipoDocumento IN ('vco', 'vcr','dco')) and IdArticulo = '01-00321' and 
IdListaEmpresa = '1000129'
GROUP BY IdTipoDocumento) AS T1

方法三：

SELECT SUM(CASE WHEN IdTipoDocumento IN ('vco', 'vcr') THEN Quantity ELSE -1*Quantity END)
AS SQ
FROM  Sales join Document on Sales.IdDocument = Document.IdDocument 
where (IdTipoDocumento IN ('vco', 'vcr','dco')) and IdArticulo = '01-00321' and 
IdListaEmpresa = 1000129

方法 3a：

   SELECT IdListaEmpresa, 
         SUM(CASE WHEN IdTipoDocumento IN ('vco', 'vcr') 
                  THEN Quantity 
                  ELSE -1*Quantity END) AS SQ
   FROM  Sales join Document on Sales.IdDocument = Document.IdDocument 
   WHERE (IdTipoDocumento IN ('vco', 'vcr','dco')) 
       AND IdArticulo = '01-00321' 
       AND IdListaEmpresa IN (1000129, 1000130, 1,2,3,4,5)
   GROUP BY IdListaEmpresa