how to save only time not date in database through sql query - mysql

this query is saving complete date and time. but i want to save only time not date in database. is there any query to do this?
update table set current_time=now();

Your column must be set to either DATETIME or TIMESTAMP.
If you use the TIME type then your query would work as expected.
If you are using any other type of column then you could use CURTIME() method or CAST(column AS TIME) as mentioned by other answers, however this would use more space on disk, and make for much slower queries if you use to select, and prevent you from various operators:
e.g. SELECT * FROM table WHERE current_time<'12:00'
You can see more information about the different DATE column types here: https://dev.mysql.com/doc/refman/5.7/en/date-and-time-types.html
Note that the CURTIME() method is not a standard SQL function, so this would only work on MySql

U can use CONVERT (time, SYSDATETIME()) as the value.
This automates your process without using Current_time=now();
INSERT INTO table SET current_time = CONVERT (time, SYSDATETIME());
You can also use curtime();
INSERT INTO table SET current_time = curtime();
Credits: Salmaan C

Related

change dateformat string in mysql table from number (milliseconds) to actual date

I have one tale users which have stored "date Of Birth" in int(11) data type. I want to convert this in to Date type using mysql.
this is actual my database user table
is there any way to direact convert this int type of datatype which is actually stored using strtotime function from PHP. So I am migrating this table in new database I want to change this field datatype to date.
Yes, the function is called FROM_UNIXTIME().
http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_from-unixtime
So, something like:
ALTER User Table ADD dateOfBirthAsDate DATETIME;
UPDATE User Set dateOfBirthAsDate = FROM_UNIXTIME(`DateBirth`);
You can use MAKETIME
MAKETIME( milliseconds /1000,milliseconds / (60*60),
millimilliseconds / 60,
seconds % 60 )
Also check FROM_UNIXTIME
FROM_UNIXTIME(`date Of Birth`);

Issue of updating existing table with results of select statement for time zone conversion

I have a table called table1 with three columns, one of which is Date_Of_Call which is of datetime type with the data in PDT. I basically need to convert the data from PDT to UTC and put the UTC converted dates into a new column in the existing table. I added a new column with:
alter table table1 ADD Date_Of_Call_UTC DATETIME;
I am able to get the proper time conversion with this select statement:
select CONVERT_TZ(Date_Of_Call, '-7:00', '-0:00') from table1;
The issue I am having is trying to use an update command to take the results of the select statement and put them in the new Date_Of_Call_UTC column. Any thoughts of how to do this?
I tried the below statement and a few variations but can't quite figure out what I need to do:
update table1 set table1.Date_Of_Call_UTC = (select CONVERT_TZ(Date_Of_Call, '-7:00', '-0:00') from table1);
Any assistance is appreciated!
this one should work:
update table1
set table1.Date_Of_Call_UTC = CONVERT_TZ(Date_Of_Call, '-7:00', '-0:00');
NOTE: dates are usually stored already as UTC in mysql, but during output they can be displayed with offset applied, read about it: http://dev.mysql.com/doc/refman/5.0/en/datetime.html and http://dev.mysql.com/doc/refman/5.5/en/time-zone-support.html

Using IST time in mysql query

I have a table containing datetime field. I want to select records with a condition that only those records that has datetime value above current IST time.
Example
select * from mytable where dt > current_ist_datetime
current_ist_datetime is what i do not know how to use. CONVERT_TZ() with NOW() can give it. But i do not know what timezone mysql uses. that is, i do not know second parameter that i should pass to CONVERT_TZ()
You can retrieve the timezone setting for the current MySQL session with a SQL statement:
mysql> SELECT ##session.time_zone;
If the DBA has not set the timezone on MySQL, it will default to a value of SYSTEM, which represents the timezone on the operating system.
http://dev.mysql.com/doc/refman/5.5/en/time-zone-support.html
FOLLOWUP:
In a predicate as in your example SQL statement:
select * from mytable where dt > current_ist_datetime
(given dt and current_ist_datetime of datatype DATETIME)
the comparison of the values will be independent of any timezone conversion, since there is no no timezone information associated with a DATETIME value.
That is, the value returned from a column of datatype DATETIME is not affected by the time_zone setting of the MySQL server (SELECT ##global.time_zone) or of the MySQL session (SELECT ##session.time_zone).
The value returned by the NOW() function, however, will be impacted by the time_zone setting of the session.
To get that returned in IST, ensure the time_zone for the session is specified correctly, e.g.
SET VARIABLES time_zone = "+05:30"
(N.B. If the session is retrieved from and returned from a connection pool, the other users of the pool may not be expecting a different time_zone;...)
(NOTE: the above entirely ignores the confusion introduced by the JDBC driver, caused by the "impedance mismatch" (differences) between MySQL's implementation of DATETIME datatype, and Java implementation of Date object. If you are passing DATETIME values across a JDBC connection, that's whole 'nother ball of confusion.)
MySQL uses timezone in two formats; i.e. you can either use 'Asia/Calcutta' or '+05:30' (for IST). But I would suggest you use the latter one.
Timezone for UTC is '+00:00'. So you can use following query provided that dt is in UTC & current_ist_datetime is in IST
select * from mytable where dt > CONVERT_TZ(current_ist_datetime,'+05:30','+00:00')
I am using this query in my project where I paas current_ist_datetime & +05:30 from client(in IST) to my server(in UTC) & it works like a charm.
If you use NOW() mysql will select current date time of your system's timezone
select * from mytable where dt > CONVERT_TZ(NOW(),'+05:30','+00:00')
You can modify these queries according to your need.

MySQL Correct Usage of From_Unixtime in Trigger

I have the following trigger which inserts records into Table B whenever Table A is updated. This works fine however TableA_date is in unix time format and I want to convert it when the trigger inserts the record in Table B.
DELIMITER $$
CREATE TRIGGER MyTrigger
AFTER INSERT
ON TableA
FOR EACH ROW
BEGIN
INSERT INTO TableB SET
TableB_id = NEW.TableA_id,
TableB_date = FROM_UNIXTIME(NEW.TableA_date, '%d/%m/%y %r'),
TableB_comment = NEW.TableA_comment;
END $$
DELIMITER ;
In my results, instead of "01/01/70 03:00:05 AM" as the converted date I get "5" - I know the format string is correct as I am able to use it in a select statement. Thanks for your help
You are working too hard. Just leave out the format string entirely. Dates are stored as dates, not a strings.
In fact, don't even use the conversion at all! Just directly assign the date column, and MySQL will do any conversion it needs.
I'm assuming that TableA_date is stored using the timestamp datatype, and that TableB_date is datetime. (Although you may want timestamp for that one too.)
If you are using other datatypes like int, or char, then fix it. That's not the correct way to structure a database.
Just to answer your actual question (instead of telling you the correct way to do it) the date format you want is yyyy-mm-dd hh:mm:ss not what you have.

Getting timestamp using MySQL

How can I get the current timestamp using a mysql query?
Depends on which kind you're looking for.
The current integer Unix Timestamp (1350517005) can be retrieved like so:
SELECT UNIX_TIMESTAMP();
MySQL often displays timestamps as date/time strings. To get one of those, these are your basic options (from the MySQL Date & Time reference):
SELECT CURRENT_TIMESTAMP;
SELECT CURRENT_TIMESTAMP();
SELECT NOW();
CURRENT_TIMESTAMP is standard SQL and works on SQL server, Oracle, MySQL, etc. You should try to keep to the standard as much as you can.
Select current_timestamp;
just use NOW()
Full reference: http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html