I have data over time for particular users and timestamp of the form 2013-11-23 16:00:00-05 - there's by minute by minute date for each user and corresponding usage value.
So the table has values: user_ID, localminute, usage.
I am trying to aggregate usage at a day wise level, what i did so far is below s but I was looking for an easier way to do it without creating the dummy column date_event:
alter table tablename add column date_event date
update table set date_event = date(localminute)
select sum(use), date_event from tablename group by date_event
My question is about how I can extract date from timestamp and aggregate in a single query. Thanks for any help!
Just cast it to a date:
select sum(use), localminute::date
from tablename
group by localminute::date;
or using standard SQL:
select sum(use), cast(localminute as date)
from tablename
group by cast(localminute as date);
Related
I am in an introduction to sql class (using postgresql) and struggling to take simple queries to the next step. I have a single table with two datetime columns (start_time & end_time) that I want to extract as two date only columns. I figured out how to extract just the date from datetime using the following:
Select start_time,
CAST(start_time as date) as Start_Date
from [table];
or
Select end_time,
CAST(end_time as date) as End_Date
from [table];
Problem: I can't figure out the next step to combine both of these queries into a single step. I tried using WHERE but i am still doing something wrong.
1st wrong example
SELECT start_time, end_time
From baywheels_2017
WHERE
CAST(start_time AS DATE) AS Start_Date
AND (CAST(end_time AS DATE) AS End_Date);
Any help is greatly appreciated. Thanks for taking the time to look.
You don't need to select the underlying field in order to later cast it; each field in the "select" clause is relatively independent. With the table created by:
CREATE TABLE test (
id SERIAL PRIMARY KEY,
start_time TIMESTAMP WITH TIME ZONE NOT NULL,
end_time TIMESTAMP WITH TIME ZONE NOT NULL
);
INSERT INTO test(start_time, end_time)
VALUES ('2022-10-31T12:30:00Z', '2022-12-31T23:59:59Z');
You could run the select:
SELECT
cast(start_time as date) as start_date,
cast(end_time as date) as end_date
FROM test;
(You can try this out on a website like DB-Fiddle.)
I have a table where column names are like years "2020-05","2020-06", "2020-07" etc and so many years as columns.I need to select only the current month, next month and third month columns alone from this table.(DB : PostgreSQL Version 11)
But since the column names are "TEXT" are in the format YYYY-MM , How can I select only the current month and future 2 months from this table without hard-coding the column names.
Below is the table structure , Name : static_data
Required select statement is like this,The table contains the 14 months data as in the above screen shot like DATES as columns.From this i want the current month , and next 2 month columns along with their data, something like below.
SELECT "2020-05","2020-06","2020-07" from static
-- SELECT Current month and next 2 months
Required output:
It's nearly impossible to get the actual value of the current month as the column name, but you can do something like this:
select d.item_sku,
d.status,
to_jsonb(d) ->> to_char(current_date, 'yyyy-mm') as current_month,
to_jsonb(d) ->> to_char(current_date + interval '1 month', 'yyyy-mm') as "month + 1",
to_jsonb(d) ->> to_char(current_date + interval '2 month', 'yyyy-mm') as "month + 2"
from bad_design d
;
Technically, you can use the information schema to achieve this. But, like GMB said, please re-design your schema and do not approach this issue like this, in the first place.
The special schema information_schema contains meta-data about your DB. Among these is are details about existing columns. In other words, you can query it and convert their names into dates to compare them to what you need.
Here are a few hints.
Query existing column names.
SELECT column_name
FROM information_schema.columns
WHERE table_schema = 'your_schema'
AND table_name = 'your_table'
Compare two dates.
SELECT now() + INTERVAL '3 months' < now() AS compare;
compare
---------
f
(1 row)
You're already pretty close with the conversion yourself.
Have fun and re-design your schema!
Disclaimer: this does not answer your question - but it's too long for a comment.
You need to fix the design of this table. Instead of storing dates in columns, you should have each date on a separate row.
There are numerous drawbacks to your current design:
very simple queries are utterly complicated : filtering on dates, aggregation... All these operations require dynamic SQL, which adds a great deal of complexity
adding or removing new dates requires modifying the structure of the table
storage is wasted for rows where not all columns are filled
Instead, consider this simple design, with one table that stores the master data of each item_sku, and a child table
create table myskus (
item_sku int primary key,
name text,
cat_level_3_name text
);
create table myvalues (
item_sku int references myskus(item_sku),
date_sku date,
value_sku text,
primary key (item_sku, date_sku)
);
Now your original question is easy to solve:
select v.*, s.name, s.cat_level_3_name
from myskus s
inner join myvalues v on v.item_sku = s.item_sku
where
v.date_sku >= date_trunc('month', now())
and v.date_sku < date_trunc('month', now()) + interval '3 month'
I have been using postgreSQL. My table has 3 columns date, time and userId. I have to find out records between the given date and time frame. Since date and time columns are different, 'BETWEEN' clause is not providing valid results
Combine the two columns into a single timestamp by adding the time to the date:
select *
from some_table
where date_column + time_column
between timestamp '2017-06-14 17:30:00' and timestamp '2017-06-19 08:26:00';
Note that this will not use an index on date_column or time_column. You would need to create an index on that expression. Or better: use a single column defined as timestamp instead.
How to get the total count for particular date by selecting different dates.
For Example:
Record contains from '2014-04-01' to till date. Each date contains multiple records with different IST time.
How to get the total count from each date?
depending on your table structure and result you want, Query should look somewhat like this
SELECT DATE(date_column), COUNT(*)
FROM tablename
WHERE date_column IN (your_date_list)
GROUP BY date(date_column);
Have a look at the following sql (I have not tested)
SELECT date_column, COUNT(*)
FROM tablename
WHERE date_column BETWEEN date_column AND current_date
GROUP BY to_date(date_column::text,'YYYY-MM-DD')
I want to insert date and time in oracle database, I have created the table with columns
create table myadmin
( employe_id number(5),
supervisor Varchar2(20),
department Varchar2(20),
action Varchar2(20),
sdate date,
stime date)
While inserting the values below it gives an error. Please tell me how to insert the time ?
insert into myadmin
( employe_id,supervisor,department,action,sdate,stime) values
(83,'gaurav','helpdesk','pick','23-jan-2013','09:43:00');
You have to use keyword to_date for date insert in oracle like this.
to_date('23-01-2013','dd-mm-yyyy')
Basically you have to use keyword to_date('your date','your date format').
You can also add date and time together if you want and it would be something like this
to_date('23-01-2013 09:43:00','dd-mm-yyyy hh24:mi:ss')
A date in Oracle always has a date part and a time part. Having date and time in two separate columns only makes sense, if it can occur that date is null and time is not. (And still, you could set date to an improbable value like 1.1.0001 then.)
However, if you want to stick to those two separate fields, then make your string a datetime with the to_date function specifying the format used:
insert into myadmin
( employe_id,supervisor,department,action,sdate,stime) values
(83,'gaurav','helpdesk','pick',to_date('23-01-2013','dd-mm-yyyy'), to_date('09:43:00', 'hh24:mi:ss'));