Question

我最近使用此SQL语句的变体编写了一份报告：

select project.*, TF.*, TW.*, TR.*, TH.* from
(select sum(Quantity) as FQty from unitType where Type = 'F' group by type) TF, 
(select sum(Quantity) as WQty from unitType where Type = 'W' group by type) TW, 
(select sum(Quantity) as RQty from unitType where Type = 'R' group by type) TR, 
(select sum(Quantity) as HQty from unitType where Type = 'H' group by type) TH

问题是，如果一个项目没有单元类型，那么该单元类型的sql语句将返回任何内容，然后使我的整个语句不返回任何内容。我一直试图找出如何让它返回0如果为null，但似乎没有什么对我有用。我已经尝试了Case，但它告诉我一些关于＆＃34; isnull是一个无效的列名称＆＃34;我也试过＆＃34;如果存在＆＃34;但这只会引发语法错误。

有什么建议吗？

Answer 1

尝试用以下情况： SELECT SUM(QUANTITY) AS FQTY FROM (SELECT CASE WHEN QUANTITY IS NULL THEN 0 ELSE QUANTITY END QUANTITY FROM....)

Answer 2

试试这个：

OUTER APPLY (select sum(Quantity) as FQty from unitType where Type = 'F' group by type) TF
OUTER APPLY (select sum(Quantity) as WQty from unitType where Type = 'W' group by type) TW 
OUTER APPLY (select sum(Quantity) as RQty from unitType where Type = 'R' group by type) TR 
OUTER APPLY (select sum(Quantity) as HQty from unitType where Type = 'H' group by type) TH

由于您使用的CROSS JOIN，您有0行。行数为...* number of row of TF * number of row of TW *...，并想象一个产品，其中一个数字为0，结果为0。

如果为null或不为null，则返回一个值。 TSQL

2 个答案: