Question

我正在尝试根据另一列是否为空来编写一个将设置位值的查询。

例如：

UPDATE @tmpRank
SET IsXYSale = NOT dbo.Sales_XForY.ID IS NULL
FROM @tmpRank
LEFT JOIN dbo.Sales_XForY ON SaleId = @tmpRank.SaleId

我在NOT关键字上遇到语法错误，但我看不到如何更正查询。

Answer 1

SET IsXYSale = CASE WHEN dbo.Sales_XForY.ID IS NULL THEN 0 ELSE 1 END

Answer 2

UPDATE @tmpRank
SET IsXYSale = CASE WHEN dbo.Sales_XForY.ID IS NULL THEN 0 ELSE 1 END
FROM @tmpRank
LEFT JOIN dbo.Sales_XForY ON SaleId = @tmpRank.SaleId

Answer 3

SQL Server没有隐含的布尔值

UPDATE @tmpRank
SET IsXYSale = CASE WHEN dbo.Sales_XForY.ID IS NULL THEN 0 ELSE 1 END
FROM @tmpRank
LEFT JOIN dbo.Sales_XForY ON SaleId = @tmpRank.SaleId

在这种情况下，您可以利用位的工作方式：任何非零，非空值都会变为1.它假定您当然不能将0作为ID值...

SET IsXYSale = ISNULL(dbo.Sales_XForY.ID, 0)

根据空查询的结果将列更新为BIT值

3 个答案: