Various ways to migrate between utf8 and utf8mb4 MySQL character sets

01-resources.md

• https://dev.mysql.com/doc/refman/5.5/en/charset-unicode-utf8mb4.html
• https://dev.mysql.com/doc/refman/5.5/en/charset-unicode-upgrading.html

commands.sql

ALTER TABLE t1
  DEFAULT CHARACTER SET utf8mb4,
  MODIFY col1 CHAR(10)
    CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL,
  MODIFY col2 CHAR(10)
    CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL;

schema.sh

# Export
mysqldump table_name > schema.sql

# Upgrade or Downgrade
sed 's/utf8/utf8mb4/g' schema.sql > upgrade.sql
sed 's/utf8mb4/utf8/g' schema.sql > downgrade.sql

# Import
mysql table_name < upgrade.sql