TINYINT can be set to length of 4, but that doesn’t mean the max value is 9999. A tiny int will always have the same range no matter what size you specify since that isn’t what it is for with integers. It is the display width for the command line output.

This is what I was able to find in the MySQL manual:

The display width does not constrain the range of values that can be stored in the column, nor the number of digits that are displayed for values having a width exceeding that specified for the column.

Reading the manual for things like this isn’t something people normally do. I had no idea about this until recently and I’ve been using MySQL for a long time.

Reference Chart for Max Signed Integers

TINYINT 127
SMALLINT 32767
MEDIUMINT 8388607
INT 2147483647
BIGINT 9223372036854775807

However, CHAR and VARCHAR work as expected with these limits.