I want to replace all values which has a NULL value with the the value in another column on the same row.
I have tried different sql statements without any success.
Regards
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Post (add to your question) your best effort so far.PM 77-1– PM 77-12017-02-28 20:11:03 +00:00Commented Feb 28, 2017 at 20:11
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Do you mean you want to update your table in the way you describe, or that you want to perform such a replacement in the results of a query?John Bollinger– John Bollinger2017-02-28 20:12:33 +00:00Commented Feb 28, 2017 at 20:12
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What is one of the different SQL statements that you have already tried?Degan– Degan2017-02-28 20:41:00 +00:00Commented Feb 28, 2017 at 20:41
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2 Answers
If you want to update, do something like this:
update t set col1 = col2
where col1 is null
If you just want to do selection, use most databases support coalesce:
select coalesce(col1, col2) from t;
2 Comments
Rahul
what if
col2 is null itself
Yordan Grigorov
At least in Postgresql: If all arguments are null, the COALESCE function will return null
If you want to Update the value from same column
UPDATE A
SET A.Col1 = A.Col2
From TableA A
Where A.Col1 IS NULL
If you want to update the value from Other table then Try this:
Update A
SET A.Column1 = B.Column1
From TableA A
INNER JOIN TableB B
ON A.SomeID = B.SameID
WHERE A.Column1 IS NULL
You can update the value by using join and update query.
