I'm using SQL in Impala to write this query. I'm trying to convert a date string, stored in YYYYMMDD format, into a date format for the purposes of running a query like this:
SELECT datadate,
session_info
FROM database
WHERE datadate >= NOW() - INTERVAL 5 DAY
ORDER BY datadate DESC;
Since the >= NOW() - INTERVAL 5 DAY code won't work with the YYYYMMDD string, I'd like to find a way to convert that into a date format that will work with this type of query. My thought is that it should look something like this (based on similar questions about other SQL query editors), but it's not working in Impala:
SELECT datadate,
session_info,
convert(datetime, '20141008', 102) AS session_date
FROM database
WHERE session_date >= NOW() - INTERVAL 5 DAY
ORDER BY session_date DESC;
Anyone know how to do this in Impala?
EDIT:
I finally found a working solution to the problem. None of the attempts using configurations of CAST or CONVERT would work in Impala, but the below query solves the problem and is fully operational, allowing date math to be performed on a column containing string values:
SELECT datadate,
session_info
FROM database
WHERE datadate >= from_unixtime(unix_timestamp(now() - interval 5 days), 'yyyyMMdd')
GROUP BY datadate
ORDER BY datadate DESC;
Native way:
to_timestamp(cast(date_number AS STRING), 'yyyyMMdd')
See Timestamp Literals on [Link Updated 2020-08-24]:
https://docs.cloudera.com/cdp-private-cloud-base/7.1.3/impala-sql-reference/topics/impala-literals.html
You need to add the dashes to your string so Impala will be able to convert it into a date/timestamp. You can do that with something like:
concat_ws('-', substr(datadate,1,4), substr(datadate,5,2), substr(datadate,7) )
which you can use instead of datadate in your expression.
To ignore hour/minute/second... , use from_timestamp, result 2020-01-01.
select from_timestamp(cast('2020-01-01 01:01:01.000000' as TIMESTAMP),'yyyy-MM-dd');
Related
sql table
here in the table above named carpooling contains a column name start_on which has date time as timestamp i have to write a query to select all the rows having date as 25-11-20 using to_char and to_date.
You write a timestamp literal like this:
timestamp '2020-11-25 00:00:00'
so the full filtering condition will be
where start_on >= timestamp '2020-11-25 00:00:00'
and start_on < timestamp '2020-11-26 00:00:00'
Note that dates and timestamps are different in Oracle, and dates include times down to the second (this is for historical reasons - originally there was only the date type, and timestamp was added much later).
Use the TRUNC function, along with date and interval literals:
SELECT *
FROM CARPOOLING
WHERE START_ON BETWEEN DATE '2020-11-25'
AND (DATE '2020-11-26' - INTERVAL '0.000001' SECOND)
You can simply use to_date, but it's recommended to remove the time when comparing the dates. Otherwise, rows having the same date, but a different time will not be selected. Removing the time can be done using TRUNC.
So you can do something like this:
SELECT * FROM carpooling
WHERE TRUNC(start_on) = TO_DATE('2020-11-25','yyyy.mm.dd');
If you don't want to check the 25th of November 2020, but another data, change the date to match your goal.
I have a table which has a date but stored as a varchar datatype column:
my_date
metric_name
2021-09-12
CLS
2021-09-12
FID
I want to keep only 30 days back using this column.
I tried using cast(my_date as date) in the where clause, but it is not working.
Can you assist?
My code is in ANSI SQL.
You should be able to cast your column as a date. That would suggest syntax such as:
where cast(my_date as date) >= current_date - interval '30' day
That said, date/time functions are very database specific, so the exact syntax varies by database.
I'm using a SQL SELECT query to bring back all rows from a specific date.
The column I'm using is called TimeStamp (datetime)
(An example of data from this column = 01/02/2018 07:55:55)
What I would like is to return all rows from a specific date eg 24/06/2019
I have tried
SELECT top 20 TimeStamp
from Report
where TimeStamp = '02/01/2018 07:55:55'
which returns one row (which is correct as there is only one row containing this data)
If I then try
SELECT top 20 TimeStamp
from Report
where TimeStamp LIKE '02/01/2018%'
I get no results, I have also tried escaping the forward slashes
SELECT top 20 TimeStamp
from Report
where TimeStamp = '02\/01\/2018%'
Most databases support a string function called left(). If I assume that your "timestamp" is a string, then:
where left(timestamp, 10) = '01/02/2018'
However, it should be stored as a date or date/time. If so, then you can do:
where timestamp >= '2018-02-01' and
timestamp < '2018-02-02'
Note the use of standard formatted dates (YYYY-MM-DD). That is the way most databases implement date literals.
In SQL Server, you can also use:
where convert(date, timestamp) = '2018-02-01'
Both this and the previous version will use an index on timestamp, so both are reasonable solutions.
this should work
SELECT TimeStamp FROM report where convert(Date, TimeStamp) = '2019-06-24'
or select timestamp from report where timestamp between '2019-06-24' and '2019-06-25'. This will get you everything between 2019-06-24 00:00:00 and 2019-06-25 00:00:00 thus all records with date 2019-06-24
Convert timestamp value to date.
SELECT TimeStamp
FROM report
WHERE CAST(TimeStamp AS DATE) = '2019-06-24'
Having a bit of a issue with a SQL conversion from SQL Server to Oracle.
We are passing in a datetime value (in this example just 1900-01-01) and we need to select all rows that have a modified date greater than 2 days before the date passsed in. Here is the SQL syntax that works:
SELECT *
FROM TABLENAME
WHERE CAST(LAST_MODIFIED AS DATE) > CAST(DATEADD(dd, -2, '1990-01-01') AS DATE);
Where LAST_MODIFIED is a column, and the '1900-01-01' is a value being injected to the SQL String in C# prior to it being executed. Before being asked, we prefer not to subtract the 2 days from the date before passing it to the SQL :)
So what we need then is just the above query converted to Oracle syntax... We have tried a couple things and it fails :(
Thanks,
Dave
You can write this in Oracle as:
SELECT *
FROM TABLENAME
WHERE TRUNC(LAST_MODIFIED) > (DATE '1990-01-01') - 2
Notes:
In Oracle, DATE includes a time component, so casting to a date does nothing.
Oracle supports various ways to include a date/time constant. I prefer the keyword DATE with the ISO/ANSI standard date format YYYY-MM-DD.
The - 2 is perhaps more accurately written as - interval '2' day. However, the interval notation is new(ish) to Oracle.
And, it is better in either database to write this without modifying last_modified_date:
SELECT *
FROM TABLENAME
WHERE LAST_MODIFIED >= (DATE '1990-01-01') - 1
Removing the time component is not needed, with the right date comparison.
SELECT *
FROM TABLENAME
WHERE CAST(LAST_MODIFIED AS DATE) > TO_DATE('1990-01-01','YYYY-MM-DD')-2;
SELECT *
FROM TABLENAME
WHERE TRUNC( LAST_MODIFIED ) > TO_DATE( '1990-01-01', 'YYYY-MM-DD' ) - 2;
or, if you pass the value in using the :date_value bind variable:
SELECT *
FROM TABLENAME
WHERE TRUNC( LAST_MODIFIED ) > :date_value - 2;
If the value you are passing in to the query does not have a time component then you can just do:
SELECT *
FROM TABLENAME
WHERE LAST_MODIFIED >= :date_value - 1;
I'm in PostgreSQL.
I need to print all mailing with creation date strictly more that 2015-04-04. I tried the following queries:
SELECT *
FROM mailing.mailing
WHERE creation_date > '2015-04-04';
and
SELECT *
FROM mailing.mailing
WHERE creation_date >= '2015-04-04';
But they produced the same result set(including '2015-04-04'). Is it possible to write such a query without explicitly saying WHERE creation_date >= '2015-04-05';
UPD: The column's type is timestamp without time zone.
If your creation_date field is of type datetimetry comparing it to '2015-04-04 23:59:59' instead, as '2015-04-04 08:30:00' seems to be greater than '2015-04-04'.
Assuming your default date format for your database is 'YYYY-MM-DD' and creation_date field is a date type, your query will actually be converted automatically to something like:
SELECT *
FROM mailing.mailing
WHERE creation_date > to_date('2015-04-04', 'YYYY-MM-DD');
The date value you have provided represents the first second of that day, that's why you see no difference between your queries. (Your first query would exclude the first second of the day though.)
What you could do to avoid this is:
where creation_date >= to_date('2015-04-05 00:00:00', 'YYYY-MM-DD HH24:MI:SS')
or
where date_trunc(creation_date-1) = '2015-04-04'