Reads the file and returns the file contents as a string. To use this function, the file must be located on the server host, you must specify the full path name to the file, and you must have the FILE privilege. The file must be readable by the server and its size less than max_allowed_packet bytes. If the secure_file_priv system variable is set to a nonempty directory name, the file to be loaded must be located in that directory.
UPDATE t
SET blob_col=LOAD_FILE('/tmp/picture')
WHERE id=1;
If the file does not exist or cannot be read because one of the preceding conditions is not satisfied, the function returns NULL.
UPDATE t
SET blob_col=LOAD_FILE('/tmp/picture')
WHERE id=1;