MySQL supports indexing expressions directly, which is effectively the same as indexing an invisible virtual column: https://dev.mysql.com/doc/refman/8.0/en/cre

MySQL supports indexing expressions directly, which is effectively the same as indexing an invisible virtual column: https://dev.mysql.com/doc/refman/8.0/en/create-index.html#create-index-functional-key-parts https://dev.mysql.com/doc/refman/8.0/en/create-index.html#cr... MySQL supports "multi-valued indexes" over JSON data, which offer a non-obvious solution for partial indexes, since "index records are not added for empty arrays": https://dev.mysql.com/doc/refman/8.0/en/create-index.html#create-index-multi-valued https://dev.mysql.com/doc/refman/8.0/en/create-index.html#cr... MariaDB doesn't support any of this directly yet though: https://www.skeema.io/blog/2023/05/10/mysql-vs-mariadb-schema/#generated-columns https://www.skeema.io/blog/2023/05/10/mysql-vs-mariadb-schem...