A detailed description of the differences between int, bigint, smallint, and tinyint in Mysql _mysql

The recent use of MySQL database has encountered many types of numbers, mainly int,bigint,smallint and tinyint. Among them, the difference between int and smallint is confusing. Today on the internet carefully looked for, find the following content, leave file to do a summary:
An exact numeric data type that uses integer data.
bigint
Integer data (all numbers) from -2^63 (-9223372036854775808) to 2^63-1 (9223372036854775807). The storage size is 8 bytes.
P.S. bigint already has a length, in the MySQL build table length, only used to display the number of digits
int
Integer data (all numbers) from -2^31 (-2,147,483,648) to 2^31–1 (2,147,483,647). The storage size is 4 bytes. The SQL-92 synonym for int is integer.
smallint
Integer data from -2^15 (-32,768) to 2^15–1 (32,767). The storage size is 2 bytes.
tinyint
Integer data from 0 to 255. The storage size is 1 bytes.
Notes
Supports bigint data types where integer values are supported. However, bigint is used in some special cases where the integer value exceeds the range supported by the INT data type, and the bigint can be used. In SQL Server, the int data type is the primary integer data type.
In the data type precedence table, bigint is located between smallmoney and Int.
A function returns bigint only if the parameter expression is a bigint data type. SQL Server does not automatically promote other integer data types (tinyint, smallint, and int) to bigint.
Int (m) in the integer data type, m represents the maximum display width. in int (m), the value of M has nothing to do with how much storage space the Int (m) occupies. and the number of digits is also not a relationship int (3), int (4), int (8) are occupied by 4 Btyes of storage space on the disk.