INT(5) vs SMALLINT(5)

Question

In MySQL table definitions is there a different between INT(5) and SMALLINT(5)? Or do they both represent the same size?

Answer 1

No, they don't represent the same size that is allocated for the field type.

An int can be between -2147483648 and 2147483647 signed, or 0 and 4294967295 unsigned.

A smallint is between -32768 and 32767 signed, or 0 and 65535 unsigned.

The (5) represents the display width of the field. From the manual, it states:

The display width does not constrain the range of values that can be stored in the column. Nor does it prevent values wider than the column display width from being displayed correctly. For example, a column specified as SMALLINT(3) has the usual SMALLINT range of -32768 to 32767, and values outside the range permitted by three digits are displayed in full using more than three digits.

The display width, from what I can tell, can be used to left-pad numbers that are less than the defined width. So 00322, instead of 322. TBH, I've never used it.

But it doesn't affect the storage size of the column. An int will take up more space than a smallint.