What is the size of column of int(11) in mysql in

2018-12-31 19:44发布

What is the size of column of int(11) in mysql in bytes?

And Maximum value that can be stored in this columns?

标签: mysql types int
11条回答
时光乱了年华
2楼-- · 2018-12-31 20:08

According to here, int(11) will take 4 bytes of space that is 32 bits of space with 2^(31) = 2147483648 max value and -2147483648min value. One bit is for sign.

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宁负流年不负卿
3楼-- · 2018-12-31 20:11

I think max value of int(11) is 4294967295

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只靠听说
4楼-- · 2018-12-31 20:17

In MySQL integer int(11) has size is 4 bytes which equals 32 bit.

Signed value is : -2^(32-1) to 0 to 2^(32-1)-1 = -2147483648 to 0 to 2147483647

Unsigned values is : 0 to 2^32-1 = 0 to 4294967295

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谁念西风独自凉
5楼-- · 2018-12-31 20:24

A good explanation for this can be found here

To summarize : The number N in int(N) is often confused by the maximum size allowed for the column, as it does in the case of varchar(N).

But this is not the case with Integer data types- the number N in the parentheses is not the maximum size for the column, but simply a parameter to tell MySQL what width to display the column at when the table's data is being viewed via the MySQL console (when you're using the ZEROFILL attribute).

The number in brackets will tell MySQL how many zeros to pad incoming integers with. For example: If you're using ZEROFILL on a column that is set to INT(5) and the number 78 is inserted, MySQL will pad that value with zeros until the number satisfies the number in brackets. i.e. 78 will become 00078 and 127 will become 00127. To sum it up: The number in brackets is used for display purposes.
In a way, the number in brackets is kind of usless unless you're using the ZEROFILL attribute.

So the size for the int would remain same i.e., -2147483648 to 2147483648 for signed and 0 to 4294967295 for unsigned (~ 2.15 billions and 4.2 billions, which is one of the reasons why developers remain unaware of the story behind the Number N in parentheses, as it hardly affects the database unless it contains over 2 billions of rows), and in terms of bytes it would be 4 bytes.

For more information on Integer Types size/range, refer to MySQL Manual

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旧时光的记忆
6楼-- · 2018-12-31 20:24

Though this answer is unlikely to be seen, I think the following clarification is worth making:

  • the (n) behind an integer data type in MySQL is specifying the display width
  • the display width does NOT limit the length of the number returned from a query
  • the display width DOES limit the number of zeroes filled for a zero filled column so the total number matches the display width (so long as the actual number does not exceed the display width, in which case the number is shown as is)
  • the display width is also meant as a useful tool for developers to know what length the value should be padded to

A BIT OF DETAIL
the display width is, apparently, intended to provide some metadata about how many zeros to display in a zero filled number.
It does NOT actually limit the length of a number returned from a query if that number goes above the display width specified.
To know what length/width is actually allowed for an integer data type in MySQL see the list & link: (types: TINYINT, SMALLINT, MEDIUMINT, INT, BIGINT);
So having said the above, you can expect the display width to have no affect on the results from a standard query, unless the columns are specified as ZEROFILL columns
OR
in the case the data is being pulled into an application & that application is collecting the display width to use for some other sort of padding.

Primary Reference: https://blogs.oracle.com/jsmyth/entry/what_does_the_11_mean

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