MySQL: What is the meaning of Unsigned?

The settings for Signed and Unsigned regulate, whether the values of the relevant column can also be negative. If you set a column to Signed, the values can be positive or negative (they can have a sign), in the other case, if you set it to Unsigned, only positive values and zero are possible.

The advantage is obvious: If you set the column to unsigned, much wider ranges of values are covered with the same memory requirements. So, if you expect large values, but no negative ones, possibly, you can use a smaller integer type using the attribute "Unsigned" and with this, you can save space.

What savings and value ranges with Signed and Unsigned columns exactly occur with each integer type, you can experience in my little info table on all MySQL integer types.
2012-06-26 at 18:26