postgreSQL increment number in output - postgresql

I am extracting three values (server, region, max(date)) from my postgresql> But I want to extract an additional 4th field which should be the numerical addition of 1 to 3rd field. I am unable to use date add function as in the database date field is defined as an integer.
date type in DB
date|integer|not null
tried using cast and date add function
MAX(s.date)::date + cast('1 day' as interval)
Error Received
ERROR: cannot cast type integer to date
Required output
select server, region, max(alarm_date), next date from table .....
testserver, europe, 20190901, 20190902
testserver2, europe, 20191001, 20191002
next date value should be the addition to alarm_date

To convert an integer like 20190901 to a date, use something like
to_date(CAST(s.date AS text), 'YYYYMMDD')
It is a bad idea to store dates as integers like that. Using the date data type will prevent corrupted data from entering the database, and it will make all operations natural.

First solution that came to my mind:
select (20190901::varchar)::date + 1
Which output 2019-09-02 as type date.
Other solutions can be found here.

Related

Connecting BigQuery and Google Sheets - DATE parameter issue

following 1 I started creating a Spreadsheet which reads data from BigQuery, but I'm having an issue handling parameters related to date values.
In the first sheet, I created 2 cells with 2 parameters, the start and the end of a date interval, with proper values. Both cells are formatted as "Date" value.
In the second sheet I configured BigQuery connector, for this example, I'm using a public dataset with dates. bigquery-public-data.utility_eu.date_greg
From the BigQuery connector wizard I added:
"STARTDATE" as "PARAMETERS!B1"
"ENDDATE" as "PARAMETERS!B2"
After this configuration, this is the resulting query:
SELECT
date,
date_str,
date_int
FROM `bigquery-public-data.utility_eu.date_greg`
WHERE date > DATE(#STARTDATE) AND date < DATE(#ENDDATE)
LIMIT 10
I'm getting an error directly from the editor with this message:
> Error BigQuery: No matching signature for function DATE for argument types: INT64. Supported signatures: DATE(TIMESTAMP, [STRING]); DATE(DATETIME); DATE(INT64, INT64, INT64) at [8:14]
As far as I can understand, the "date" cells are retrieved as a number, so the direct parse is not working. After a couple of tests, I understood the that given int value is the number I can obtain change cell format to "number".
If you convert cell value from DATE to NUMBER you get this value:
01/05/2019 -> 43.586
31/05/2019 -> 43.616
What is this number? It is not milliseconds, it increases by 1 every next day. In order to create the proper query that can parse this int, I need to understand what is this int (of course I can handle the cell as "text" and writing the timestamp value directly, but I would prefer to have the native date format so I can use the built-in calendar.
My consideration (with simple math) is that this number refers to a number of days since 30/12/1899, but it is very odd (also, every date BEFORE this days is always 0), so I'm asking you directly how to handle this value. Basing on my understanding of when the number counter starts (30/12/1899), I created this query which add the number retrieved from the cell:
SELECT *
FROM `bigquery-public-data.utility_eu.date_greg`
WHERE
date >= DATE_ADD(DATE("1899-12-30"), INTERVAL #DATAINIZIO DAY)
AND date <= DATE_ADD(DATE("1899-12-30"), INTERVAL #DATAFINE DAY)
It is working... but I think I'm doing a workaround that is not the proper way of doing this.
Also, is there any full documentation related to this BigQuery connection provided by Spreadsheet? Besides presentation in 1 I'm unable to find any specific documentation.
Spreadsheets (Google, Excel, ...) store the dates as days passed since a starting date with a fractional day representing time.
From here: "Excel stores dates and times as a number representing the number of days since 1900-Jan-0, plus a fractional portion of a 24 hour day: ddddd.tttttt . This is called a serial date, or serial date-time."
Now, you have to ways to filter by date on your Query:
In the query, you can use DATE_ADD to add your number of days (cell value) to the base date. (Carefull, DATE_ADD takes INT, and the date value is float so needs prior casting).
(preferred) on your spreadsheet you use TEXT(cell, "yyyy-mm-dd") so you can then use DATE() in the BigQuery query.
I use the second method as, though you need that extra cell (unless you directly store the date as YYYY-MM-DD; keeps the query cleaner than having a cast and date_add in there. Also would save you from the "1904 problem" explained in the link above.
What is this number? It is not milliseconds, it increases by 1 every next day.
This is so called serial number which represent number of days since "very beginning"
Google's Spreadsheet date calendar starts from 1900-01-01 - which is treated as a "very beginning"
In order to create the proper query that can parse this int, I need to understand what is this int
Armed with above info you can adjust you dates calculation to be in sync with what BigQuery expects
You mentioned that your fields are already in Date format, maybe you are doing an extra parsing in your query.
Try to do it without the DATE functions.
Also, I found this other doc, not merely related to connection, but might be helpful: Getting info from Spreadsheets with BigQuery.

Converting long (numbers) text datatype (with blank values) to date

I have troubles converting HubSpot UNIX timestamp to date. Timestamp is stored as text value.
Value looks like this:
1549324800000
My logic was first to convert the number to bigint and later converted it to date using:
TO_CHAR(TO_TIMESTAMP(properties__vape_station__value)), 'DD/MM/YYYY')
What would be the best way to achieve converting UNIX Timestamp in text type to date in PostgreSQL 11.
You can cast the value in that column to a bigint and then use to_timestamp.
But apparently that column also stores empty strings rather than NULL values if no value is present, so you need to take that into account:
to_timestamp(nullif(trim(properties__vape_station__value),'')::bigint/1000)
This would still fail however if anything else than a number is stored in that column.

Converting string timestamp into date

I have dates in a postgres database. The problem is they are stored in a string field and have values similar to: "1187222400000" (which would correspond to 07.08.2007).
I would like to convert them into readable dates usind some SQL to_date() expression or something similar but can't come up with the correct syntax to make it work.
There really isn't enough information here for a conclusion, so I propose this 'scientific-wild-ass-guess' to resolve your puzzle. :)
It appears this number is UNIX 'epoch time' in milliseconds. I'll show this example as if your string field had the arbitrary name, 'epoch_milli'. In postgresql you can convert it to a time stamp using this statement:
SELECT TIMESTAMP WITH TIME ZONE 'epoch' + epoch_milli * INTERVAL '1 millisecond';
or using this built-in postgresql function:
SELECT to_timestamp(epoch_milli / 1000)
either of which, for the example '1187222400000', produces the result
"2007-08-15 17:00:00-07"
You can do some of your own sleuthing with quite a few values selected similarly to this:
SELECT to_timestamp(epoch_milli/1000)::DATE
FROM (VALUES (1187222400000),(1194122400000)) AS val(epoch_milli);
"Well, bollocks, man. I just want the date." Point taken.
Simply cast the timestamp to a date to discard the excess bits:
SELECT to_timestamp(epoch_milli / 1000)::DATE
Of course its possible that this value is a conversion or is relative to some other value, hence the request for a second example data point.

Is ISO8601 the best date-format for PostgreSQL jsonb when i want to filter by the date?

I'm new to PostgreSQL and I have the following question:
I have a table with just an id-column and a data-column, which uses the jsonb-type. Inside the jsonb-object I have a datetime field. I read in various posts, that I should use the ISO-8601 dateformat to store in the DB.
I want to filter my table by date like this:
SELECT * FROM table WHERE data->'date' > '2016-01-01T00:00'
Is this really the best date-format for this purpose?
Thanks in advance :)
IMHO Your query should produce
ERROR: operator does not exist: jsonb > timestamp with time zone
If I get it right. In case you change -> to ->> it should get a text value instead of jsonb field (which is also not comparable to timestamp).
It should be smth like
SELECT * FROM table WHERE (data->>'date')::timestamptz > '2016-01-01T00:00' to work
The big advantage of that format is that string order corresponds to date order, so a comparison like the one you quote in your question would actually work as intended.
A second advantage is that a timestamp in that format can easily be converted to a PostgreSQL timestamp with time zone value, because the type input function understands this format.
I hope you are not dealing with dates “before Christ”, because it wouldn't work so easily with those.

Comparing two time columns in ASP.NET

I'm rather new to ASP.NET and SQL, so I'm having a tough time trying to figure out how to compare two time columns. I have a timestamped column and then a Now() column in an .mdb database. I need to have a gridview display records that are "Greater than or equal to 3 hours" from the timestamp. Any idea how I can accomplish this?
The Transact-SQL timestamp data type is a binary data type with no time-related values.
So to answer your question: Is there a way to get DateTime value from timestamp type column?
The answer is: No
You need another column of datetime2 type and use > operator to for comparison. You might want to set default value of getutcdate() to set it when each row is inserted.
UPDATE:
Since the column is of datetime type and not timestamp type (there is a type in SQL Server called timestamp, hence the confusion) you can just do
WHERE [TimeCalled] <= DATEADD(hour, -3, GETDATE())
Make sure your server is running in the same timezone as your code. It may be safer to store all dates in UTC. In that case use GETUTCDATE instead on GETDATE
Timestamps are generally used to track changes to records, and are updated every time the record is changed. If you want to store a specific value you should use a datetime field.
If you're using a DateTime Column and you want the result in TSQL try
DATEDIFF(Hour, 'Your DateTime Column here', 'pass Now() here' )
try to execute this example in TSQL:
select DATEDIFF(Hour, '2012-11-10 00:00:59.900', '2012-11-10 05:01:00.100')