Following is my SQL query, it throws an error:-
CREATE TABLE IF NOT EXISTS USER_PROFILE(Id INT PRIMARY KEY AUTO_INCREMENT, date DATETIME NOT NULL DEFAULT NOW) ;
It says Invalid default value for 'date'.
I've tried synonyms for NOW() as well, namely CURRENT_TIMESTAMP, but still the same error.
How can I create a column date with default value current time?
On the documentation page, it says to assign this way
CREATE TABLE t1 (
ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
dt DATETIME DEFAULT CURRENT_TIMESTAMP
);
From the document
The DEFAULT value clause in a data type specification indicates a
default value for a column. With one exception, the default value must
be a constant; it cannot be a function or an expression. This means,
for example, that you cannot set the default for a date column to be
the value of a function such as NOW() or CURRENT_DATE. The exception
is that you can specify CURRENT_TIMESTAMP as the default for TIMESTAMP
and DATETIME columns
So no function is allowed in the default value hence the first query is failing.
Again from the document
As of MySQL 5.6.5, TIMESTAMP and DATETIME columns can be automatically
initializated and updated to the current date and time (that is, the
current timestamp). Before 5.6.5, this is true only for TIMESTAMP, and
for at most one TIMESTAMP column per table. The following notes first
describe automatic initialization and updating for MySQL 5.6.5 and up,
then the differences for versions preceding 5.6.5.
Before 5.6.5, this is true only for TIMESTAMP
So your mysql version is less than 5.6.5 hence the 2nd query is failing too.
So you need to create the table as
CREATE TABLE IF NOT EXISTS
USER_PROFILE
(
Id INT PRIMARY KEY AUTO_INCREMENT,
date TIMESTAMP DEFAULT CURRENT_TIMESTAMP
) ;
It might be that DATE, as a reserved word, is confusing it by the time it gets to the DEFAULT clause. Try a different name and if that works, try quoting "date".
Related
I executed the following query on my mysql server:
CREATE TABLE user(
created_at timestamp NOT NULL,
updated_at timestamp NOT NULL,
id integer NOT NULL AUTO_INCREMENT PRIMARY KEY,
count integer NOT NULL,
name varchar(50) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE utf8_general_ci
When I looked into phpmyadmin I was suprised.
The created_at column had a default set to CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP was also there.
How can this even happen?
It shouldnt do that, right?
Although this behavior is surprising to me, it is actually explained in the documentation:
For any TIMESTAMP or DATETIME column in a table, you can assign the
current timestamp as the default value, the auto-update value, or
both:
An auto-initialized column is set to the current timestamp for inserted rows that specify no value for the column.
An auto-updated column is automatically updated to the current timestamp when the value of any other column in the row is changed
from its current value. An auto-updated column remains unchanged if
all other columns are set to their current values. To prevent an
auto-updated column from updating when other columns change,
explicitly set it to its current value. To update an auto-updated
column even when other columns do not change, explicitly set it to the
value it should have (for example, set it to CURRENT_TIMESTAMP).
It is possible to set default value on DATE (NOT DATETIME) column in MySQL 5.7 to current date?
I try this (generated by Workbench):
ALTER TABLE `db`.`table` CHANGE COLUMN `column` `column` DATE NOT NULL DEFAULT CURDATE() ;
but not works for me.
(no data in table)
No, you cannot. The documentation is pretty clear on this:
This means, for example, that you cannot set the default for a date
column to be the value of a function such as NOW() or CURRENT_DATE.
The exception is that you can specify CURRENT_TIMESTAMP as the default
for TIMESTAMP and DATETIME columns. See Section 12.3.5, “Automatic
Initialization and Updating for TIMESTAMP and DATETIME”.
You can do one of the following:
Set up a column with a default value for the DATETIME. Create view that extracts the date as a separate column.
Create an insert trigger to set the date column.
There is a way you can do this if you have another column that has a for example a datetime field with a default of NOW(). See this post:
I have a table with two timestamp fields. They are not nullable. The problem is that whenever I insert null into those fields, the current date is automatically saved, instead of throwing an error saying "Column 'first_data_dt' cannot be null", just like it happens when I insert a value into another non-nullable field.
There are no triggers associated to this table.
Does anybody know why this is happening?
EDIT to add table definition:
CREATE TABLE `ui_mytable` (
`id` int(11) NOT NULL,
`first_data_dt` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`last_data_dt` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
I understand now why first_data_dt is updated to the current timestamp anytime I insert null. But what about last_data_dt?
That's what a TIMESTAMP column does:
The TIMESTAMP data type offers automatic initialization and updating to the current date and time (that is, the current timestamp). [...] You can initialize or update any TIMESTAMP column to the current date and time by assigning it a NULL value, unless it has been defined with the NULL attribute to permit NULL values.
Source: MySQL documentation
Maybe you want to use a DATETIME instead?
Creating a database table in MySQL. I have created two fields to grab timestamps.
created_at timestamp default '0000-00-00 00:00:00',
updated_at timestamp default now() on update now(),
When I update the database, both fields are updating to the current timestamp. Any thoughts on how to prevent this from happening? I am not providing the 'created_at' field when I update -- I am also providing 'null' for the updated_at field to auto update.
Depending on the version of MySQL you should be able to use the following for your default value on the updated_at field:
CURRENT_TIMESTAMP on UPDATE CURRENT_TIMESTAMP
Your created_at field should just have CURRENT_TIMESTAMP as the default.
I would also set both to the datatype datetime instead of timestamp.
Timestamp initialisation can be an ugly beast in mysql!
Based on the commment below you have mysql v5.6.4 or earlier:
I can't have two current_timestamps declared without getting an error -- and although it's default is 0 -- it is producing a current timestamp upon creation(without me feeding in the timestamp) – Spencer Rohan
You can have a single timestamp field that are initialised and/or updated to the current timestamp when you insert / update your record. In earlier versions this had to be the 1st timestamp field in the table.
I would simply set the created_at to be a nullable column with a default value of null because according to mysql documentation on timestamp initialization:
In other words, a TIMESTAMP column defined to permit NULL values auto-initializes only if its definition includes DEFAULT CURRENT_TIMESTAMP
By changing the default value to null you go around any problems you may have with zero dates and various sql modes.
created_at timestamp null default null,
NOTE: The question is about DATE type, not Datetime nor Timestamp
How to alter column of date data type to use current date by default?
I saw a lot of examples for datetime (with time part), but not for date. I have tried:
ALTER TABLE `accounting` ALTER `accounting_date`
SET DEFAULT CURRENT_DATE;
ALTER TABLE `accounting` CHANGE `accounting_date`
`accounting_date` DATE NOT NULL DEFAULT CURRENT_DATE;
I also tried with CURDATE(), NOW(), CURRENT_DATE() ...
MySQL 8.0+:
CREATE TABLE foo (
`creation_time` DATE DEFAULT (DATE_FORMAT(NOW(), '%Y-%m-%d'))
)
I use version 8.0.26, this is working:
datecolumn date DEFAULT (CURDATE())
It does not work, if you don't use the brackets!
Probably you cannot set default value for 'date' data type in mysql. You need to change the type to timestamp or datetime.
You may have a look at this similar question.
Invalid default value for 'Date'
EDIT:
In version 5.6.5, it is possible to set a default value on a datetime column, and even make a column that will update when the row is updated. The type definition:
CREATE TABLE foo (
`creation_time` DATETIME DEFAULT CURRENT_TIMESTAMP,
`modification_time` DATETIME ON UPDATE CURRENT_TIMESTAMP
)
Reference: http://optimize-this.blogspot.com/2012/04/datetime-default-now-finally-available.html
As noted in this question Invalid default value for 'create_date' timestamp field, this error may happen when MySQL is in strict mode (which is default behavior, I believe).
If you want to override it, just disable all these checks when creating your table:
SET SQL_MODE='ALLOW_INVALID_DATES';
The warning will be still generated, however it will allow to create the table.
It seems to work in sqlite:
"date" DATE NOT NULL DEFAULT (DATE(CURRENT_TIMESTAMP))
No, you cannot. The documentation is pretty clear on this:
This means, for example, that you cannot set the default for a date column to be the value of a function such as NOW() or CURRENT_DATE. The exception is that you can specify CURRENT_TIMESTAMP as the default for TIMESTAMP and DATETIME columns.