I'm hoping that there is a simple fix for this. I have a database column in which I store a number. I knew that the numbers would get pretty big, so I set the field to 'bigint'. However it will not store a number larger than 9223372036854775808.
Why is this?
Quoting from the manual:
BIGINT[(M)] [UNSIGNED] [ZEROFILL]
A large integer. The signed range is -9223372036854775808 to 9223372036854775807. The unsigned range is 0 to 18446744073709551615.
You've hit the bigint maximum size. This is a limitation due to the way the number is stored on the computer. It's the maximum size number you can represent with 8 bytes.
If you need to store a bigger number, consider using another method. You could use varchars but you will need to convert if you're doing math operations on it.
I think you're using a signed BIGINIT:
Range of a signed bigint: -9223372036854775808 - 9223372036854775807
Range of an unsigned bigint: 0- 18446744073709551615
Use ALTER TABLE to modify the column:
ALTER TABLE t1 MODIFY col1 BIGINT UNSIGNED;
Related
I want to convert a CSV database into a MySQL one, I know I will never add any new row in the database tables. I know the max ID of each table, for example : 9898548.
What should be the proper way to compute the int size ? Does a CEIL(LOG2(last_id)) could be sufficient for this ? With my example, it would be LOG2(9898548) = 23.2387 so int(24) ? is this correct ?
When you're defining your table and you know your max values you can refer to the max table sizes. See http://dev.mysql.com/doc/refman/5.7/en/integer-types.html for a table of numeric sizes.
IDs are usually positive so you can use the unsigned numbers. In your case 9898548 is less than 16777215 (the unsigned MEDIUMINT max value) so that would be the most space efficient storage option. So your calculation is correct. You need 24 bits or 3 bytes, or a UNSIGNED MEDIUMINT.
CREATE TABLE your_table (id UNSIGNED MEDIUMINT PRIMARY KEY);
The brackets with numbers inside are to help MySQL display the number correctly, they don't do anything to the storage size. So INT(11) and INT (24), can both sure the same range of numbers. But the one defined INT (11) will only display a number with a column width of equivalent to 11 digits even if the number is smaller. See
http://dev.mysql.com/doc/refman/5.7/en/numeric-type-attributes.html
"This optional display width may be used by applications to display integer values having a width less than the width specified for the column by left-padding them with spaces"
Yes, in this case, you need an integer type with a least 24 bits (equals 3 bytes). The smallest in MySQL satisfying this is UNSIGNED MEDIUMINT, according to the documentation.
Edit: Added the UNSIGNED.
I was trying to add a number with a length of 11 but when I input it in the database it can't. If I try to add a number with a length of 10 it can.
This is the error:
ERROR 1264: 1264: Out of range value for column 'contact_no' at row 1
SQL Statement:
INSERT INTO `mcs`.`new_table` (`id`, `contact_no`) VALUES ('1', '12345678901')
It's not clear what question you are asking.
Why is this error being returned?
Likely, the contact_no column is declared with datatype of INT, a 32-bit integer, and you attempted to assign a value larger than the supported maximum value.
The maximum value for a signed 32-bit integer is 2,147,483,647. (that decimal value of 2^31-1. For an unsigned 32-bit integer, maximum value is 2^32.)
Some other question that wasn't asked
If you need to store values larger than the maximum supported by the INT datatype, you could define the column as a different datatype.
For example, BIGINT gives a maximum value of 2^63-1 for unsigned.
If you need a maximum of 12 decimal digits, you could use a DECIMAL(12) datatype.
Change your data type of contact_no to BIGINT.
Check range of different data type at MYSQL official website.
I personally recommend you to use varchar, as you don't need to compare contact number with any field.
Please check datatype of contact_no column.
'12345678901' is exceeding its size.
I have a MySQL database and I am wondering about the consequences of the varchar size on my query performances.
For example, what would be the difference between a varchar(10) and a varchar(50) in terms of the performances or database size.
If I have something like 10000 rows, would it affect a lot on performances or is it insignificant?
Note : I don't do any join on this column (if that is important)
varchar(10) means that maximum allowed bytes is 10 and varchar(50) means that maximum allowed bytes is 50. Basically, a varchar(10) is no different disk-wise than a varchar(128).So, in whatever manner you declare your columns, it wont make a difference on the storage end. But it will certainly make a difference while making a query.
From the source:
Values in VARCHAR columns are variable-length strings. The length can
be specified as a value from 0 to 255 before MySQL 5.0.3, and 0 to
65,535 in 5.0.3 and later versions. The effective maximum length of a
VARCHAR in MySQL 5.0.3 and later is subject to the maximum row size
(65,535 bytes, which is shared among all columns) and the character
set used.
There shouldn't be any real difference in performances between a VARCHAR(10) and VARCHAR(50).
The real difference would be between CHAR and VARCHAR.
http://dev.mysql.com/doc/refman/5.0/en/char.html
The length of a CHAR column is fixed to the length that you declare
when you create the table. The length can be any value from 0 to 255.
When CHAR values are stored, they are right-padded with spaces to the
specified length. When CHAR values are retrieved, trailing spaces are
removed.
Values in VARCHAR columns are variable-length strings. The length can
be specified as a value from 0 to 255 before MySQL 5.0.3, and 0 to
65,535 in 5.0.3 and later versions. The effective maximum length of a
VARCHAR in MySQL 5.0.3 and later is subject to the maximum row size
(65,535 bytes, which is shared among all columns) and the character
set used. See Section E.7.4, “Limits on Table Column Count and Row
Size”.
Replacing every VARCHAR by CHAR columns might improve performances, since then, rows will have fixed size, thus reducing fragmentation and somehow optimizing disks access.
That being said, if you have only 10000 rows, I doubt you would see any real difference, unless maybe if you have unusually "long" rows.
I am inserting value
insert into user (name,fbid) Values ('Adi Mathur',100000564553314)
but in the database i see the value if fbid to be
2147483647
Why ? How should i fix it ?
fbid int(50)
As explained in the manual, the maximum value of a (signed) INT, which occupies 4 bytes/32 bits, is 2,147,483,647; for integer data types, the number in parenthesis is the display width, which only affects the way that the data is displayed, not how much space it is allocated for storage:
M indicates the maximum display width for integer types. For floating-point and fixed-point types, M is the total number of digits that can be stored (the precision). For string types, M is the maximum length. The maximum permissible value of M depends on the data type.
You probably want a BIGINT.
I want to use a temporary MEMORY table to store some intermediate data, but I need/want it to support TEXT columns. I had found a workaround involving casting the TEXT to a VARCHAR or something, but like an idiot I didn't write down the URL anywhere I can find now.
Does anyone know how to, for example, copy a table x into a memory table y where x may have TEXT columns? If anyone knows how to cast columns in a "CREATE TABLE y SELECT * FROM x" sorta format, that would definitely be helpful.
Alternatively, it would help if I could create a table that uses the MEMORY engine by default, and "upgrades" to a different engine (the default maybe) if it can't use the MEMORY table (because of text columns that are too big or whatever).
You can specify a SELECT statement after CREATE TEMPORARY TABLE:
CREATE TEMPORARY TABLE NewTempTable
SELECT
a
, convert(b, char(100)) as b
FROM OtherTable
Re comment: it appears that CHAR is limited to 512 bytes, and you can't cast to VARCHAR. If you use TEXT in a temporary table, the table is stored on disk rather than in memory.
What you can try is defining the table explicitly:
CREATE TEMPORARY TABLE NewTempTable (
a int
, b varchar(1024)
)
insert into NewTempTable
select a, b
from OtherTable
You can use varChar(5000). No need to cast. If you have example data, you can use it as a measure. There is 64Kb space.
The length can be specified as a value from 0 to 255 before MySQL 5.0.3, and 0 to 65,535 in 5.0.3 and later versions. The effective maximum length of a VARCHAR in MySQL 5.0.3 and later is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used.
Do you mean CAST(text_column AS CHAR)? Note that you shouldn't need it, MySQL will cast it automatically if the target column is VARCHAR(n).