I have two date time columns in my database:
inserted and updated
inserted timestamp DEFAULT CURRENT_TIMESTAMP
updated timestamp -------------------------
Primary column is ID.
I run SQL command:
REPLACE INTO TABLE1 (id,name,updated) VALUES ('1','test1',NOW())
And this is OK:
inserted column get current time upon the first INSERT
updated columns is also set to current time because it is set in REPLACE command.
If I run second command to update name, then updated column is being updated properly but also and INSERTED column is updated also. I do not want that!!!
REPLACE INTO TABLE1 (id,name,updated) VALUES ('1','test2',NOW())
How to stop inserted column to be updated automatically once the REPLACE command is being run? What change on column INSERTED in mysql database should be done? I must use REPLACE sql or any synonym for my needs.
replace deletes the old record and inserts a new one.
If you want to update an existing record use update instead:
UPDATE TABLE1
SET name = 'test2',
updated = now()
where id = 1
If you want to update a field without write-in SQL command. You need to create that column like that:
`inserted` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
`updated` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
But this one works for Update operations not Replace operations.
REPLACE works exactly like INSERT, except that if an old row in the table has the same value as a new row for a PRIMARY KEY or a UNIQUE index, the old row is deleted before the new row is inserted. See Section 13.2.6, “INSERT Syntax”.
Detailed explanations here, see: https://dev.mysql.com/doc/refman/8.0/en/replace.html
Related
If I have a column in a table of type TIMESTAMP and has as default: CURRENT_TIMESTAMP does this column get updated to the current timestamp if I update the value
of any other column in the the same row?
It seems that it does not but I am not sure if this is what should happen.
I can not understand what this means (from MySQL documentation):
If the column is auto-updated, it is automatically updated to the
current timestamp when the value of any other column in the row is
changed from its current value. The column remains unchanged if all
other columns are set to their current values. To prevent the column
from updating when other columns change, explicitly set it to its
current value. To update the column even when other columns do not
change, explicitly set it to the value it should have]2
Give the command SHOW CREATE TABLE whatever
Then look at the table definition.
It probably has a line like this
logtime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
in it. DEFAULT CURRENT_TIMESTAMP means that any INSERT without an explicit time stamp setting uses the current time. Likewise, ON UPDATE CURRENT_TIMESTAMP means that any update without an explicit timestamp results in an update to the current timestamp value.
You can control this default behavior when creating your table.
Or, if the timestamp column wasn't created correctly in the first place, you can change it.
ALTER TABLE whatevertable
CHANGE whatevercolumn
whatevercolumn TIMESTAMP NOT NULL
DEFAULT CURRENT_TIMESTAMP
ON UPDATE CURRENT_TIMESTAMP;
This will cause both INSERT and UPDATE operations on the table automatically to update your timestamp column. If you want to update whatevertable without changing the timestamp, that is,
To prevent the column from updating when other columns change
then you need to issue this kind of update.
UPDATE whatevertable
SET something = 'newvalue',
whatevercolumn = whatevercolumn
WHERE someindex = 'indexvalue'
This works with TIMESTAMP and DATETIME columns. (Prior to MySQL version 5.6.5 it only worked with TIMESTAMPs) When you use TIMESTAMPs, time zones are accounted for: on a correctly configured server machine, those values are always stored in UTC and translated to local time upon retrieval.
I think you have to define the timestamp column like this
CREATE TABLE t1
(
ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
See here
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 explain it let's imagine you have only one row:
-------------------------------
| price | updated_at |
-------------------------------
| 2 | 2018-02-26 16:16:17 |
-------------------------------
Now, if you run the following update column:
update my_table
set price = 2
it will not change the value of updated_at, since price value wasn't actually changed (it was already 2).
But if you have another row with price value other than 2, then the updated_at value of that row (with price <> 3) will be updated to CURRENT_TIMESTAMP.
Add a trigger in database:
DELIMITER //
CREATE TRIGGER update_user_password
BEFORE UPDATE ON users
FOR EACH ROW
BEGIN
IF OLD.password <> NEW.password THEN
SET NEW.password_changed_on = NOW();
END IF;
END //
DELIMITER ;
The password changed time will update only when password column is changed.
Adding where to find UPDATE CURRENT_TIMESTAMP because for new people this is a confusion.
Most people will use phpmyadmin or something like it.
Default value you select CURRENT_TIMESTAMP
Attributes (a different drop down) you select UPDATE CURRENT_TIMESTAMP
If I have a column in a table of type TIMESTAMP and has as default: CURRENT_TIMESTAMP does this column get updated to the current timestamp if I update the value
of any other column in the the same row?
It seems that it does not but I am not sure if this is what should happen.
I can not understand what this means (from MySQL documentation):
If the column is auto-updated, it is automatically updated to the
current timestamp when the value of any other column in the row is
changed from its current value. The column remains unchanged if all
other columns are set to their current values. To prevent the column
from updating when other columns change, explicitly set it to its
current value. To update the column even when other columns do not
change, explicitly set it to the value it should have]2
Give the command SHOW CREATE TABLE whatever
Then look at the table definition.
It probably has a line like this
logtime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
in it. DEFAULT CURRENT_TIMESTAMP means that any INSERT without an explicit time stamp setting uses the current time. Likewise, ON UPDATE CURRENT_TIMESTAMP means that any update without an explicit timestamp results in an update to the current timestamp value.
You can control this default behavior when creating your table.
Or, if the timestamp column wasn't created correctly in the first place, you can change it.
ALTER TABLE whatevertable
CHANGE whatevercolumn
whatevercolumn TIMESTAMP NOT NULL
DEFAULT CURRENT_TIMESTAMP
ON UPDATE CURRENT_TIMESTAMP;
This will cause both INSERT and UPDATE operations on the table automatically to update your timestamp column. If you want to update whatevertable without changing the timestamp, that is,
To prevent the column from updating when other columns change
then you need to issue this kind of update.
UPDATE whatevertable
SET something = 'newvalue',
whatevercolumn = whatevercolumn
WHERE someindex = 'indexvalue'
This works with TIMESTAMP and DATETIME columns. (Prior to MySQL version 5.6.5 it only worked with TIMESTAMPs) When you use TIMESTAMPs, time zones are accounted for: on a correctly configured server machine, those values are always stored in UTC and translated to local time upon retrieval.
I think you have to define the timestamp column like this
CREATE TABLE t1
(
ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
See here
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 explain it let's imagine you have only one row:
-------------------------------
| price | updated_at |
-------------------------------
| 2 | 2018-02-26 16:16:17 |
-------------------------------
Now, if you run the following update column:
update my_table
set price = 2
it will not change the value of updated_at, since price value wasn't actually changed (it was already 2).
But if you have another row with price value other than 2, then the updated_at value of that row (with price <> 3) will be updated to CURRENT_TIMESTAMP.
Add a trigger in database:
DELIMITER //
CREATE TRIGGER update_user_password
BEFORE UPDATE ON users
FOR EACH ROW
BEGIN
IF OLD.password <> NEW.password THEN
SET NEW.password_changed_on = NOW();
END IF;
END //
DELIMITER ;
The password changed time will update only when password column is changed.
Adding where to find UPDATE CURRENT_TIMESTAMP because for new people this is a confusion.
Most people will use phpmyadmin or something like it.
Default value you select CURRENT_TIMESTAMP
Attributes (a different drop down) you select UPDATE CURRENT_TIMESTAMP
need an advice, how to auto-store datetime value for my historyActivity table in select insert mysql query. This is an example:
INSERT INTO history_sequence(CODE, LAST_MOUNTH, LAST_VALUE) SELECT CODE, MOUNTH, VALUE FROM seq WHERE CODE = CODEVALUE
i just want to add datetime to see time when the data inserted. Need help please
You can do this in the MySQL table definition:
ALTER TABLE history_sequence ADD inserted TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP;
When records are inserted into the table table, the inserted column gets automatically populated with the current timestamp.
If I have a column in a table of type TIMESTAMP and has as default: CURRENT_TIMESTAMP does this column get updated to the current timestamp if I update the value
of any other column in the the same row?
It seems that it does not but I am not sure if this is what should happen.
I can not understand what this means (from MySQL documentation):
If the column is auto-updated, it is automatically updated to the
current timestamp when the value of any other column in the row is
changed from its current value. The column remains unchanged if all
other columns are set to their current values. To prevent the column
from updating when other columns change, explicitly set it to its
current value. To update the column even when other columns do not
change, explicitly set it to the value it should have]2
Give the command SHOW CREATE TABLE whatever
Then look at the table definition.
It probably has a line like this
logtime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
in it. DEFAULT CURRENT_TIMESTAMP means that any INSERT without an explicit time stamp setting uses the current time. Likewise, ON UPDATE CURRENT_TIMESTAMP means that any update without an explicit timestamp results in an update to the current timestamp value.
You can control this default behavior when creating your table.
Or, if the timestamp column wasn't created correctly in the first place, you can change it.
ALTER TABLE whatevertable
CHANGE whatevercolumn
whatevercolumn TIMESTAMP NOT NULL
DEFAULT CURRENT_TIMESTAMP
ON UPDATE CURRENT_TIMESTAMP;
This will cause both INSERT and UPDATE operations on the table automatically to update your timestamp column. If you want to update whatevertable without changing the timestamp, that is,
To prevent the column from updating when other columns change
then you need to issue this kind of update.
UPDATE whatevertable
SET something = 'newvalue',
whatevercolumn = whatevercolumn
WHERE someindex = 'indexvalue'
This works with TIMESTAMP and DATETIME columns. (Prior to MySQL version 5.6.5 it only worked with TIMESTAMPs) When you use TIMESTAMPs, time zones are accounted for: on a correctly configured server machine, those values are always stored in UTC and translated to local time upon retrieval.
I think you have to define the timestamp column like this
CREATE TABLE t1
(
ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
See here
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 explain it let's imagine you have only one row:
-------------------------------
| price | updated_at |
-------------------------------
| 2 | 2018-02-26 16:16:17 |
-------------------------------
Now, if you run the following update column:
update my_table
set price = 2
it will not change the value of updated_at, since price value wasn't actually changed (it was already 2).
But if you have another row with price value other than 2, then the updated_at value of that row (with price <> 3) will be updated to CURRENT_TIMESTAMP.
Add a trigger in database:
DELIMITER //
CREATE TRIGGER update_user_password
BEFORE UPDATE ON users
FOR EACH ROW
BEGIN
IF OLD.password <> NEW.password THEN
SET NEW.password_changed_on = NOW();
END IF;
END //
DELIMITER ;
The password changed time will update only when password column is changed.
Adding where to find UPDATE CURRENT_TIMESTAMP because for new people this is a confusion.
Most people will use phpmyadmin or something like it.
Default value you select CURRENT_TIMESTAMP
Attributes (a different drop down) you select UPDATE CURRENT_TIMESTAMP
I want to create a table with two column, one "created" and one "modified", with a timestamp type. I don't want them to have a default value. But when I create them, it automatically puts CURRENT_TIMESTAMP as default for at least one of them, and also on update.
How can I just have type timestamp with no default or on update value for any of my column?
Edit: I use MySQL
If you are using SQL Server, the timestamp type is used for row versioning, not for storing an actual date or time value. See MSDN.
You could create the columns with a datetime datatype and then set your created and modified values with triggers.
CREATE TRIGGER trg_SetDateCreated ON MyTable
FOR INSERT AS
UPDATE MyTable
SET created = CURRENT_TIMESTAMP
WHERE MyTable.id = (SELECT Id FROM Inserted);
GO
CREATE TRIGGER trg_SetDateModified ON MyTable
FOR UPDATE AS
UPDATE MyTable
SET modified = CURRENT_TIMESTAMP
WHERE MyTable.id = (SELECT Id FROM Inserted);
GO