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PreparedStatement update does not update on NULL values

Posted on 2014-04-06
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Last Modified: 2016-06-04
Hi Experts

I am trying to update a field with NULL values without success, but If I put an empty String the update works. The problem with putting an empty string is - my column field "fruitname" accepts unique values. I am using JDBC. see below what I am trying to do.

update fruits_tbl set uxservernames=concat(fruitname, \r\n'" + fruitname + "') where fruit_id=" +fruit_id)

The columns

fruit_id (INT) PRK | fruitname (VARCHAR(255) | fruitdescr VARCHAR(255)|

The fruitname column can hold a NULL value.

Thank you.
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Question by:jw124210
3 Comments
 
LVL 34

Accepted Solution

by:
Dan Craciun earned 95 total points
ID: 39981728
CONCAT returns NULL if any of the operators are NULL.

If you want to avoid this, us
CONCAT_WS('\r\n', fruitname, 'peach')

CONCAT_WS will simply skip any NULL values.

HTH,
Dan
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LVL 109

Expert Comment

by:Ray Paseur
ID: 39982795
In my experience MySQL NULL does not match an empty string of zero length.   However if the columns are defined NOT NULL DEFAULT '' an empty string will match.
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