Date filteration in Postgre SQL - postgresql

I am looking to get the row which has the date is equal to 2017-01-12. The date has field type timestamp without time zone. I tried
SELECT * FROM tabl WHERE date = 2017-01-12;
What is the correct syntax?

try:
SELECT * FROM tabl WHERE date = '2017-01-12';

If that doesn't work, try an explicit cast:
SELECT *
FROM tabl
WHERE date = DATE '2017-01-12';

Related

How to run the postgres query with date as input on the column with timestamp in long format

I want to query postgres database table which has the column with timestamp in long milliseconds. But I have the time in date format "yyyy-MM-dd HH:mm:ssZ" like this. How can I convert this date format to long milliseconds to run the query?
You can either convert your long value to a proper timestamp:
select *
from the_table
where to_timestamp(the_millisecond_column / 1000) = timestamp '2020-10-05 07:42'
Or extract the seconds from the timestamp value :
select *
from the_table
where the_millisecond_column = extract(epoch from timestamp '2020-10-05 07:42') * 1000
The better solution is however to convert that column to a proper timestamp column to avoid the constant conversion between (milliseconds) and proper timestamp values

Extract Only Date from timestamp in postgres

I have a 'timestamp without time zone' value in a column example:
PunchIn = "2019-06-10 09:10:00"
How can I extract "2019-06-10 00:00:00" from this column?
demo:db<>fiddle
SELECT my_date::date::timestamp
This converts the date column my_date to date (cuts the time part) and if you cast it back into timestamp it gets the 0 time.
Alternatively you can use the date_trunc function:
SELECT date_trunc('day', my_date)
SELECT SUBSTRING("PunchIn = '2019-06-10 09:10:00'" FROM 11 FOR 21);
should return the string you're looking for (if I count the index number right:)
You can use the DATE function to extract date:
SELECT DATE(SUBSTRING("PunchIn = '2019-06-10 09:10:00'" FROM 11 FOR 21));

Convert packed DB2 iseries value to YYYY-MM-DD

I'm trying to select records from a DB2 Iseries system where the date field is greater than the first of this year.
However, the date fields I'm selecting from are actually PACKED fields, not true dates.
I'm trying to convert them to YYYY-MM-DD format and get everything greater than '2018-01-01' but no matter what I try it says it's invalid.
Currently trying this:
SELECT *
FROM table1
WHERE val = 145
AND to_date(char(dateShp), 'YYYY-MM-DD') >= '2018-01-01';
it says expression not valid using format string specified.
Any ideas?
char(dateshp) is going to return a string like '20180319'
So your format string should not include the dashes.. 'YYYYMMDD'
example:
select to_date(char(20180101), 'YYYYMMDD')
from sysibm.sysdummy1;
So your code should be
SELECT *
FROM table1
WHERE val = 145
AND to_date(char(dateShp), 'YYYYMMDD') >= '2018-01-01';
Charles gave you a solution that converts the Packed date to a date field, and if you are comparing to another date field, this is a good solution. But if you are comparing to a constant value or another numeric field, you could just use something like this:
select *
from table1
where val = 145
and dateShp >= 20180101;

Converting date format in denodo database

I'm trying to convert value for DIM_DT_ID to MMddYY. I'm successful in doinf that. However, query fails because ultimately I'm comparing a character value to date here. Is there a way by which I can get value for DIM_DT_ID in MMddyy format and its data type still remains DATE ?
Here DIM_DT_ID
SELECT DIM_DT_ID
DIM_DT_ID >= FORMATDATE('MMddyy',ADDDAY(TO_date('yyyy-MM-dd','2016-12-21'), -25)); from abc;
Regards,
Ajay
In Denodo, to convert a string to a date field, use "to_date()" (which returns a date).
Then, don't convert back to a string, leave that field as a date (so don't use "Formatdate()", which returns a string).
So:
SELECT *
FROM MyTable
WHERE now() >= to_date('yyyy-MM-dd',myStringFieldThatLooksLikeADate)
In my example, "now()" is a date, and so is the output of the to_date function... so you can do a comparison.
If you try to convert the date back to a string using formatdate, it won't work:
#This doesn't work:
SELECT *
FROM MyTable
WHERE now() >= formatdate('MMddyy',to_date('yyyy-MM-dd',myStringFieldThatLooksLikeADate))
It doesn't work because we are comparing a date ("now()") to a string.

sqlite date comparison

I have column of type date time and values are getting stored in format 10-29-2011 08:25.
I would like to find out the rows only which are less then current date-time. What will be the condition for date comparison for current date and this date-time column field?
Thanks.
you could use the datetime function
SELECT * FROM mytable
WHERE mydate > datetime('now')
you can even make date operations
SELECT * FROM mytable
WHERE mydate > datetime('now','-15 days')