Convert string to date in google big query - date

I have a string column which has date value in the below format
6/1/2020 12:00:00 AM
I want only the date part and convert the column to date
so when i use date_trunc and parse date like below it is giving error
select CAST(DATE_TRUNC(PARSE_DATE('%m/%d/%Y', datecolumn), AS DATE)) from table name
PLease let me know what is the best way to achieve this

Use below
select date(parse_datetime('%m/%d/%Y %I:%M:%S %p', datecolumn))
from your_table

Related

Converting string to date , datetime or Int in Mapping dataflow

I have a parquet file with a start_date and end_date columns
Formatted like this
01-Jan-2021
I've tried every combination conversion toDate, toString, toInterger functions but I still get Nulls returned when viewing the data (see image).
I would like to have see the result in two ways YYYYMMDD as integer column and YYYY-MM-DD as Date columns.
eg 01012021 and 01-01-2021
I'm sure the default format has caused this issue.
Thanks
First, for the Date formatter, you need to first tell ADF what each part of your string represents. Use dd-MMM-yyy for your format. Then, use a string formatter to manipulate the output as such: toString(toDate('01-Jan-2021', 'dd-MMM-yyyy'), 'yyyy-MM-dd')
For the integer representation: toInteger(toString(toDate('01-Jan-2021', 'dd-MMM-yyyy'), 'yyyyMMdd'))
Ah, you say *"I would like to have see the result in two ways YYYYMMDD as integer column and YYYY-MM-DD as Date columns. eg 01012021 and 01-01-2021"* Do you want in YYYYMMDD or dd-mm-yyy cause your example is in the later format.
Anyways, please see below expression you could use:
My source:
Use derived column:
Edit expression:
start_date_toInteger : toString(toDate(substring(start_date,1,11), 'dd-MMM-yyyy'), 'yyyymmdd')
start_date_toDate: toString(toDate(substring(start_date,1,11), 'dd-MMM-yyyy'), 'yyyy-mm-dd')
Final results:

How to convert string 'yyyy-mm-dd' to date format in presto sql

In presto SQL, the date is saved as a string like '2020-06-10'. I want to convert into a date format (yyyy-mm-dd)
This is how I did it:
select date_format(date_parse('2020-06-10', '%Y-%m-%d'),'%Y-%m-%d')
First I convert string to a timestamp format, then convert the new timestamp to date_format.
My question is that is there a function such that I convert only once?
For example
date_parse(string, format, expect_out_put_time_format)
You can use date function, which is a shortcut for CAST(x AS date).
presto> SELECT date('2020-06-10');
_col0
------------
2020-06-10

Teradata character to date conversion

I have a string associated with date in ‘Teradata’ tables
Var1=09OCT2017-EMRT
I need to extract the date from the above string in ‘mm/dd/yyyy’ format
I tried the following
Cast(cast(substr(var1,1,9) as char(20)) as date format ‘mm/dd/yyyy’) as date
I am getting error as ‘invalid date supplied for var1’
I would appreciate your help
You need to apply a format matching the input string:
To_Date(Substr(var1,1,9), 'ddmonyyyy')
returns a DATE.
If you want to cast it back to a string:
To_Char(To_Date(Substr(var1,1,9), 'ddmonyyyy'), 'mm/dd/yyyy')

How to add only date like 'DD/MM/YYYY' to timestamp in PostgreSQL?

I'm trying to add only the current date in "DD/MM/YYYY" format in a field of type ' timestamp in PostgreSQL' .
I try:
select to_char(now(),'DD/MM/YYYY') as date;
But PostgreSQL return me:
TIP : You will need to rewrite the expression or apply a type conversion.
There is no such thing as "only the date" in a timestamp field. A timestamp field will store timestamps.
Try using the date type instead. Please read about this here.
Also, please consider using the ISO 8601 format instead. Getting used to it helps in a lot of cases.
Human-readable formats like "DD/MM/YYYY" should only be used for presentation.
If you want to use timestamp fields and insert a human-readable formatted dates, then you are looking for:
to_timestamp('05/04/2016', 'DD/MM/YYYY')
If it is about the current date, then Postgres provides the CURRENT_DATE function, which you may use:
SELECT CURRENT_DATE;
INSERT INTO t (timestamp_field) VALUES (CURRENT_DATE);

How to convert d/MM/yyyy data to dd/MM/yyyy in sql server table?

I have create one field in sql server database as nvarchar datatype and store some date like 'd/MM/yyyy' and 'dd/MM/yyyy' format previously. Now i want to get all data in 'dd/MM/yyyy' format using query it is possible?
You can cast the field to datetime in the query:
select cast(YourField as datetime)
from YourTable
where isdate(YourField) = 1
The where isdate(YourField) = 1 part is necessary to filter out rows where the value is no valid date (it's a nvarchar field, so there could be things like abc in some rows!)
But you should really change the field to datetime in the long term, as already suggested by Christopher in his comment.
Casting like described above is always error-prone because of the many different data formats in different countries.
For example, I live in Germany where the official date format is dd.mm.yyyy.
So today (December 9th) is 9.12.2011, and running select cast('9.12.2011' as datetime) on my machine returns the correct datetime value.
Another common format is mm/dd/yyyy, so December 9th would be 12/9/2011.
Now imagine I have a nvarchar field with a date in this format on my German machine:
select cast('12/9/2011' as datetime) will return September 12th (instead of December 9th)!
Issues like this can easily be avoided by using the proper type for the column, in this case datetime.