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pdate table set name=concat(COALESCE(name,''),"fff")

update table set name=concat(ifnull(name,''),"fff")

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SQL code:
update table set name=concat(IFNULL(name,''),'fff');


SQL code:
mysql> select concat(IFNULL(null,''),'fff');
+-------------------------------+
| concat(IFNULL(null,''),'fff') |
+-------------------------------+
| fff |
+-------------------------------+
1 row in set (0.08 sec)

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