MySQL BLOB Tools - Import, Export, View and Edit

• Import file data to MySQL BLOB
• Export MySQL BLOB data to files
• View and edit BLOB data stored in MySQL
• View and edit image stored in MySQL BLOB field
• View PDF stored in MySQL BLOB field
• Batch export MySQL query results BLOB data to files
• Batch update MySQL table BLOB data from files
• Batch insert MySQL table BLOB data from files

MySQL BLOB - type family and size limits

Type in MySQL / MariaDB	Maximum size
TINYBLOB	255 bytes
BLOB	64 KB
MEDIUMBLOB	16 MB
LONGBLOB	4 GB

BLOB versus CLOB in MySQL / MariaDB

MySQL has no type called CLOB - the TEXT family takes its place. Both measure length in bytes, but TEXT is decoded with the column character set and takes part in sorting and comparison, while BLOB is treated as opaque binary.

What limits you first

The ceiling you actually hit is not the 4 GB column limit but max_allowed_packet (4 MB by default on MySQL 5.7, 64 MB on 8.0). A single value larger than that fails at the protocol layer.

BLOB from the command line

• Export: mysqldump (writes BLOBs as hex by default) or SELECT ... INTO DUMPFILE
• Import: LOAD_FILE() - restricted by secure_file_priv - or mysqlimport

Things that bite with BLOB in MySQL / MariaDB

• Leave max_allowed_packet at its default and the 4 GB LONGBLOB ceiling is unreachable
• BLOB and TEXT columns cannot have a default value and cannot be indexed whole - only a prefix index such as col(255)
• mysqldump writes BLOB values as hex literals, so the dump is about twice the size of the data; --hex-blob just makes that explicit
• InnoDB stores large values off-page - with ROW_FORMAT=COMPACT or REDUNDANT only 768 bytes stay in the row