Summary

information_schema.COLUMNS.DATA_TYPE is tinyint for BOOLEAN (TINYINT(1)), not tinyint(1) / boolean. TableMutationEngine._isBoolType looks for tinyint(1) — bool columns are treated as numeric.

BIT/BLOB/BINARY go through resultCellToDisplayString → toString(). JSON is text-typed (OK if the driver returns a string). COLUMN_TYPE / display width is not fetched.

docker/mysql/init/02_all_types.sql already has the types.

Scope

• Use COLUMN_TYPE (or tinyint + display width / COLUMN_COMMENT) so BOOLEAN stays 0/1 / TRUE/FALSE.
• Display BIT/BLOB as hex; persist the same.
• Tests against all_mysql_types (or a subset): boolean, bit, blob, json.

Out of scope

• AUTO_INCREMENT INSERT listing (separate if needed; same engine as fix(postgres): INSERT must omit GENERATED ALWAYS columns and use DEFAULT for empties #792).