SQL db2 查询条件 where column not in () 而 column value is null
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db2 query condition where column not in () while the column value is null
提问by Panadol Chong
Good day,
再会，
I have a row of data with a column, call status, the value inside is null.
我有一行数据，一列，调用状态，里面的值为空。
If I query select * from table where status not in ('EXP'), before I run this query, I thought I can select the row of data because status=null, consider not in ('EXP')also. After I tried, I found that I cant query out this row of data. Wish to know why this happen.
如果我查询select * from table where status not in ('EXP')，在我运行这个查询之前，我想我可以选择数据行，因为status=null，not in ('EXP')也考虑一下。试了下，发现这行数据查询不出来。想知道为什么会这样。
Try to Google it but maybe my question is not correct so I cant get correct search result from Google.
尝试谷歌它，但也许我的问题不正确，所以我无法从谷歌获得正确的搜索结果。
Kindly advise.
好心提醒。
回答by
NULL values are only checked with IS NULLor IS NOT NULL
NULL 值仅使用IS NULL或检查IS NOT NULL
SELECT *
FROM table
WHERE status NOT IN ('EXP')
OR status IS NULL;
Hope I have understand your question.
希望我明白你的问题。
Maybe the other way around
也许反过来
SELECT *
FROM table
WHERE status NOT IN ('EXP')
AND status IS NOT NULL;
