An UNSIGNED type cannot be negative, but on the other hand it has twice as large a range for the positive integers. The types TINYINT, SMALLINT, MEDIUMINT,
INT and BIGINT all have signed and unsigned versions.
For INT the ranges are defined as follows:
Type Storage Min Max
INT 4 -2147483648 2147483647
INT UNSIGNED 4 0 4294967295
The signed and unsigned types take the same storage space (4 bytes for INT).
See the documentation for more details.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…