Question

如何将以下SQL语句简化为1个WHERE子句：

SELECT * 
FROM tabA 
WHERE (colCar IS NULL OR colCar = '') 
   OR (colBike IS NULL OR colBike = '') 
   OR (colTrain IS NULL OR colTrain = '')

UPDATE tabA 
SET Distance = 999 
WHERE (colCar IS NULL OR colCar = '') OR 
      (colBike IS NULL OR colBike = '') OR 
      (colTrain IS NULL OR colTrain = '')

这句话没有道理，但工作正常。

我只想避免两次使用WHERE子句。

一些想法？

提前谢谢！迈克

SQL Server

SELECT * 
FROM tabA 
WHERE (colCar IS NULL OR colCar = '') 
   OR (colBike IS NULL OR colBike = '') 
   OR (colTrain IS NULL OR colTrain = '')

UPDATE tabA 
SET Distance = 999 
WHERE (colCar IS NULL OR colCar = '') 
   OR (colBike IS NULL OR colBike = '') 
   OR (colTrain IS NULL OR colTrain = '')

代码运行正常

Answer 1

您可以使用OUTPUT子句返回更新的行：

UPDATE tabA 
SET Distance = 999
OUTPUT deleted.colCar
     , inserted.colCar
     , deleted.colBike
     , inserted.Distance
WHERE (colCar IS NULL OR colCar = '') OR 
      (colBike IS NULL OR colBike = '') OR 
      (colTrain IS NULL OR colTrain = '')

更新并选择一个语句（带有1个WHERE子句）

1 个答案: