How to replace text in MySQL database

Syntax

update (table name) set (column name) = replace(column name,'search string','replacement');

Example
Remove all the half-width/full-width spaces from a table.

update test_table set column1 = replace(column1,' ','');<-- half-width space
update test_table set column1 = replace(column1,' ','');<-- full-width space
update test_table set column2 = replace(column2,' ','');
update test_table set column2 = replace(column2,' ','');
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