I want to add a new column in table so i am running following mysql command.
alter table student add doe datetime not null default curdate();
But it says I have error in mysql statement near curdate();
Modify your query as below.
ALTER TABLE `student` ADD `doe` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ;
it should solve your answer.
Thanks
Amit
The error occurs because you can't use function as default value.
It is available from MySQL version 5.6.5. Check this:
http://optimize-this.blogspot.co.uk/2012/04/datetime-default-now-finally-available.html
Previous versions can deal with timestamp type:
ALTER TABLE student ADD doe TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP;
You should use this:
alter table student add doe datetime not null default now();
Related
I am programming a ConsoleController command for edit some values in some Databases.
The problem is when I try to save the Model.
//console/controllers/ConsoleController.php
public function actionChangeCourseTitle()
{
$model = Course::find->where([ 'id' => $id])->all();
$model->title = "new title";
$model->detachBehaviors(); //for deactivate the TimestampBehavior
$model->save();
}
I want to deactivate the automatic save of the timestamp in the field "update_at", with the $model->detachBehaviors() as explained in the yii2 documentation (https://www.yiiframework.com/doc/guide/2.0/en/concept-behaviors#detaching-behaviors). But does not works.
Do you have any idea why does not works? am I defining wrong the detachBehaviors()?
Best Regards,
Paul
Update: it was edited in the SQL Definition of the table.
CREATE TABLE course (
...
updated_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
...
)
I solve the problem with ALTER COLUMN as SQL Query...
ALTER TABLE course
MODIFY COLUMN updated_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP;
and I could edit the fields without updating automaticly the field "update_at".
Update: it was edited in the SQL Definition of the table.
CREATE TABLE course ( ...
updated_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
... )
I solve the problem with ALTER COLUMN as SQL Query...
ALTER TABLE course MODIFY COLUMN updated_at datetime NOT NULL DEFAULT CURRENT_TIMESTAMP;
and I could edit the fields without updating automaticly the field "update_at".
I am using:
'time' type(datetime) defult value(CURRENT_TIMESTAMP)
but it doesn't work, it's showing the following error:
Invalid default value for 'Date'
Please can anybody help me?
If you are running MySQL version 5.6.5 or later
In your CREATE TABLE you can declare a column like this:
`mydtcol` DATETIME DEFAULT CURRENT_TIMESTAMP
Before 5.6, it's not possible to use CURRENT_TIMESTAMP for a DATETIME column. It is possible with the first TIMESTAMP column in a table.
`mytscol` TIMESTAMP DEFAULT CURRENT_TIMESTAMP
If you require the column to be DATETIME datatype, and you need the value of the column initialized when you insert a row, you can either provide a value for the column in the INSERT statement, e.g.
INSERT INTO mytable (...,mycol,...) VALUES (...,'2016-04-21 23:55:55',...)
Or, you could use a BEFORE INSERT trigger to assign a value to the column.
DELIMITER $$
CREATE TRIGGER mytable_bi
BEFORE INSERT ON mytable
FOR EACH ROW
BEGIN
IF new.mydtcol IS NULL THEN
SET new.mydtcol = NOW();
END IF;
END$$
DELIMITER ;
I have a field in a MySQL database with default value as current_timestamp
and i wish to insert value as follows:
e.g. 2014-01-25 03:53:14 to 2014-01-25 00:00:00
How can i do this?
Any suggestion or idea would be great help!!!
what you should do is change the type of your field to DATE type. Then create a trigger to SET NEW.field = CURDATE().
Here's an example in sqlFiddle
CREATE TRIGGER default_my_timestamp BEFORE INSERT ON yourTable
FOR EACH ROW
SET NEW.timestamp = CURDATE();
This seems like a really simple one but I'm struggling to figure it out. I want a column in my database that lists when a record was first created and another column that says when it was updated. It's my understanding I should be able to do all this just using MySQL. All help is appreciated :)
This stinks still no answer, reasons I'm already starting to miss Ruby on Rails...
You will probably need to use a combination of the Datetime datatype and the Timestamp data type. I would set my created column as a DateTime with a DEFAULT NOW(), and my updated column as a Timestamp with DEFAULT CURRENT_TIMESTAMP and an ON UPDATE CURRENT_TIMESTAMP attribute.
Here are the docs for the Timestamp dt:
http://dev.mysql.com/doc/refman/5.0/en/timestamp.html
In a CREATE TABLE statement, the first TIMESTAMP column can be declared in any of the following ways:
With both DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP clauses, the column has the current timestamp for its default value, and is automatically updated.
With neither DEFAULT nor ON UPDATE clauses, it is the same as DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP.
With a DEFAULT CURRENT_TIMESTAMP clause and no ON UPDATE clause, the column has the current timestamp for its default value but is not automatically updated.
With no DEFAULT clause and with an ON UPDATE CURRENT_TIMESTAMP clause, the column has a default of 0 and is automatically updated.
With a constant DEFAULT value, the column has the given default and is not automatically initialized to the current timestamp. If the column also has an ON UPDATE CURRENT_TIMESTAMP clause, it is automatically updated; otherwise, it has a constant default and is not automatically updated.
To fulfill your question and for others viewing this question, here is the answer. Note this was written for MySQL 5.x.
DROP TABLE IF EXISTS `test1`;
CREATE TABLE `test1` (
`id` INT NULL AUTO_INCREMENT ,
`name` varchar(50) NOT NULL ,
`created` DATETIME ,
`updated` DATETIME ,
PRIMARY KEY (`id`),
INDEX (`name`)
);
DELIMITER $$
DROP TRIGGER IF EXISTS `test1_created`$$
CREATE TRIGGER `test1_created` BEFORE INSERT ON `test1`
FOR EACH ROW BEGIN
SET NEW.`created` = UTC_TIMESTAMP();
SET NEW.`updated` = UTC_TIMESTAMP();
END;
$$
DROP TRIGGER IF EXISTS `test1_updated`$$
CREATE TRIGGER `test1_updated` BEFORE UPDATE ON `test1`
FOR EACH ROW BEGIN
SET NEW.`updated` = UTC_TIMESTAMP();
END;
$$
DELIMITER ;
Note
You could use TIMESTAMP for the updated column which would have automatically updated the value thus not requiring the BEFORE UPDATE trigger, however TIMESTAMP has a range from 1970 to 2038 which is fast approaching and I like to think my applications will live forever :). Although TIMESTAMP is only 4bytes while DATETIME is 8bytes.
TIMESTAMP range '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC
DATETIME range '1000-01-01 00:00:00' to '9999-12-31 23:59:59'
From the MySQL 5.0 Certification Guide:
CREATE TABLE ts_test5 (
created TIMESTAMP DEFAULT 0,
updated TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
data CHAR(30)
);
To control the initialization and update behaviour of a TIMESTAMP column, you add either or both of the DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP attributes to the column defintion when creating the table with CREATE TABLE...
and
...if you do not specify either of the DEFAULT CURRENT_TIMESTAMP or ON UPDATE CURRENT_TIMESTAMP attributes when creating a table, MySQL automatically assigns BOTH to the first TIMESTAMP column
Also
you cannot use DEFAULT CURRENT_TIMESTAMP with one column and ON UPDATE CURRENT_TIMESTAMP with another
If you can't use the timestamp fields with default attributes that Paul W has suggested, you can use AFTER INSERT and AFTER UPDATE triggers to populate the fields.
You will need two fields "Created" and
"Updated" with type datetime. When a
new entry is inserted then insert
"Created" with current time stamp.
When a update is happening insert
"Updated" with the current time stamp,
and let the "Created" field remain as
it is.
For current time stamp you can use
NOW() in your mysql query.
i have a table that looks like this:
Field: msg_sent_datetime
Type: datetime
yet when i use NOW() in a php mysql insert query it is staying as all zeros?
any idea why?
If you're using it only at the time of INSERT, you could make the field a TIMESTAMP and set a default of CURRENT_TIMESTAMP.
Without knowing more about the code it's difficult to suggest much else.
Example with CURRENT_TIMESTAMP
CREATE TABLE example (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
msg TEXT,
msg_sent_datetime TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
Also, if you want it to always update when there's a change to the row, you can add the ON UPDATE CURRENT_TIMESTAMP property to the table definition:
CREATE TABLE example (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
msg TEXT,
msg_sent_datetime TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
Of course, all of this is totally dependent on switching to TIMESTAMP which you may not want
I dont knw exactly why, but mysql has 2 datetime functions: now() and sysdate(). Perhaps you can substitute now() with sysdate() to help you troubleshoot.
http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_sysdate