Oracle SQL更新查询仅更新值为空的值 [英] Oracle SQL update query only update values if they are null

问题描述

我有以下查询，仅在它们为空时才在其中更新值.

I have the following queries where I am updating values only if they are null.

是否可以将所有这些都放在一个查询中?

Is it possible to put all of these into a single query?

UPDATE test
SET test1 = 'hello'
WHERE test1 IS NULL

和

UPDATE test
SET test2 = 'world'
WHERE test2 IS NULL

推荐答案

您可以尝试:

UPDATE test
   SET test1 = NVL(test1, 'hello'),
       test2 = NVL(test2, 'world')
 WHERE test2 IS NULL
    OR test1 IS NULL;

尽管即使对于实际上未更改的行，它也可能会触发更新触发器.

Though it may fire your update triggers even for the rows that are effectively unchanged.

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