set min length to fields in mysql

hi am new to sql can anyone help me with it.

I want to create a field example code date_type int auto increment with min size 9 that is that number should be 000000001,000000002...000000010...开发者_如何学Python.

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Use ZEROFILL. Here is an example:

CREATE TABLE zerofill_test (f1 INT(4) ZEROFILL,f2 INT(4));
INSERT INTO zerofill_test VALUES ( 1, 1 ), (10000, 10000);

Here f1 is defined with 'ZEROFILL' of 'int' type and f2 is simple int. When data is selected with SELECT command it shows you the desired result.

SELECT * FROM zerofill_test;
 +-------+-------+
 | h     | m     |
 +-------+-------+
 |  0001 |     1 |
 | 10000 | 10000 |
 +-------+-------+

For you purpose, the size of int field should be 9 i.e. `date_type int(9) ZEROFILL'