What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?
In what cases should these be used?
Answers
They take up different amounts of space and they have different ranges of acceptable values.
Here are the sizes and ranges of values for SQL Server, other RDBMSes have similar documentation:
Turns out they all use the same specification (with a few minor exceptions noted below) but support various combinations of those types (Oracle not included because it has just a
NUMBER
datatype, see the above link): SQL Server MySQL Postgres DB2
tinyint X X
smallint X X X X
mediumint X
int / integer X X X X
bigint X X X X
And they support the same value ranges (with one exception below) and all have the same storage requirements:
tinyint
: 1 byte, -128 to +127 / 0 to 255 (unsigned)smallint
: 2 bytes, -32,768 to +32,767 / 0 to 65,535 (unsigned)mediumint
: 3 bytes, -8,388,608 to 8,388,607 / 0 to 16,777,215 (unsigned)int
/integer
: 4 bytes, -2,147,483,648 to +2,147,483,647 / 0 to 4,294,967,295 (unsigned)bigint
: 8 bytes, -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 / 0 to 18,446,744,073,709,551,615 (unsigned)
The "unsigned" types are only available in MySQL, and the rest just use the signed ranges, with one notable exception:
tinyint
in SQL Server is unsignedand has a value range of 0 to 255
Those seem to be MySQL data types.
According to the documentation they take:
- tinyint = 1 byte
- smallint = 2 bytes
- mediumint = 3 bytes
- int = 4 bytes
- bigint = 8 bytes
And, naturally, accept increasingly larger ranges of numbers.
The difference is the amount of memory allocated to each integer, and how large a number they each can store.
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