ERROR:Incorrect string value

Recently write a demo, build a table, they discovered storage Chinese garbled?
Incorrect string value xx error
online only need to query the field of coding utf8 changed to
modify the field coding statement is as follows:
the ALTER TABLE product_category the CHANGE category_name category_name VARCHAR (64-) CHARACTER the SET utf8;

Reproduced in: https: //www.jianshu.com/p/88918132b757