oracle 使用 if 语句 PL/SQL 更新表
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Update table with if statement PL/SQL
提问by Matt
I am trying to do something like this but am having trouble putting it into oracle coding.
我正在尝试做这样的事情，但在将它放入 oracle 编码时遇到了麻烦。
BEGIN
IF ((SELECT complete_date FROM task_table WHERE task_id = 1) IS NULL)
THEN
UPDATE task_table SET complete_date = //somedate WHERE task_id = 1;
ELSE
UPDATE task_table SET complete_date = NULL;
END IF;
END;
But this does not work. I also tried
但这不起作用。我也试过
IF EXISTS(SELECT complete_date FROM task_table WHERE task_id = 1)
with no luck.
没有运气。
回答by Rajesh Chamarthi
I don't think you'd need the procedural block if your actual logic is like the one above.
如果您的实际逻辑与上面的逻辑类似，我认为您不需要程序块。
Assuming this is your task:
假设这是您的任务：
"if the value of complete_date for id 1 is NULL, update it with XXX. Otherwise set it to null".
“如果 id 1 的 complete_date 的值为 NULL，则用 XXX 更新它。否则将其设置为 null”。
You could just run ...
你可以跑...
Update task_table
set complete_date = nvl2(complete_date,NULL, <**your date**>)
where task_id = 1;
This will only update those records where the complete_date is null with your new date.
这只会用您的新日期更新那些 complete_date 为空的记录。
回答by Gigatron
What is the intention of this part?
这部分的意图是什么？
IF ((SELECT complete_date FROM task_table WHERE task_id = 1) IS NULL)
Is it to find if there are rows where complete_date is null and task_id = 1?
是否要查找是否存在 complete_date 为 null 且 task_id = 1 的行？
Or is it to check if there are no rows where task_id = 1?
还是要检查是否没有 task_id = 1 的行？
