The role of M in MySQL Int (m)

Int (m) This m represents the width of the display

Function: In the front-end to display an integer type of data, the database set the corresponding data type int (4), but the data written less than 4 bits, then the left padding space (if Zerofill is turned on, then fill 0), to ensure enough 4 bits, Then in the front-end display when the character is corresponding to the 4 width of the requirements.

It is emphasized in parentheses that the use of this M mainly depends on the needs of your program (Whether it is used or not are up to the application)

The display width does not limit the range of values that can be stored in the column.

This is according to the official understanding above, see: http://dev.mysql.com/doc/refman/5.6/en/numeric-type-attributes.html

The role of M in MySQL Int (m)