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I want to know is there any way to concat a string with NULL as in a table of my database there are some fields with "NULL" and I want to add some string like "Abc" with in all rows in that field like
update tablename set post=CONCAT(post,"","Job") where id=234;
Here id is primary key and now after running this if any row contains NULL in that post field then this update returns NULL otherwise ok.
Your qn is unclear.
SQL NULL is not a value, its 'flag' in the DB stating that there is no value (not a value) in that field.
You cannot concatenate onto or with a NULL, its a meaningless statement.
Hi thanks.
After posting here I too found that on mysql site after searching and As you said any operation with NULL returns NULL. Anyway, I wrote a php script to find out which records contained NULL value in that particular field and made update without concat function.
I want to know is there any way to concat a string with NULL as in a table of my database there are some fields with "NULL" and I want to add some string like "Abc" with in all rows in that field like
update tablename set post=CONCAT(post,"","Job") where id=234;
Here id is primary key and now after running this if any row contains NULL in that post field then this update returns NULL otherwise ok.
Now how to add string with NULL?
I see that you have solved your problem however if others are looking for a solution, I would just use a simple if statement.
update tablename set post=if(post is null,"Job",CONCAT(post,"","Job")) where id=234;
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