Converting date to character format in SQL

问题

I'm trying to convert a date format stored m/d/yyyy to a 'yyyymmdd' character format, without the need to cast the date column every time I want to use the column in my query.

Currently I'm casting and formatting dates as chars: ((cast(cast(invitation_date as CHAR(8)) as date format 'YYYYMMDD')).

Is there a way to convert the data column once and call the converted character value later in the query?

I'm using Teradata in Aqua Data Studio 13.0.3.

回答1:

If source is a DECIMAL yyyymmdd you can do

CAST(invitation_date - 19000000 AS DATE) AS newcol

Teradata allows an alias to be used in any place, so you can simply do

WHERE newcol > DATE

Of course best case would be to change those columns to DATE during load.

回答2:

Navigate to File->Options -> Results Format -> Teradata. Then select the datatype Date and enter yyyyMMdd. Your result set will now return the specified date format. Let me know if this will solve your issue.

回答3:

select to_char(field, 'yyyy-mm--dd hh:mm:ss') from table; 

回答4:

You shouldn't put it like this, it simply won't work:

select invitationdate(field, 'yyyymmdd')

try this instead :

SELECT to_char(column_date, 'yyyy/mm/dd') from table;

as "man" said. please pay attention to the undescore (_) character; not this (-) one.

回答5:

Here is a longer but in a way simpler way that works

select yourdate ,cast((extract(year from yourdate)*100 + extract(month from yourdate))*100 + extract(day from yourdate) as char(8)) as yyyymmdd from ...

来源：https://stackoverflow.com/questions/21914444/converting-date-to-character-format-in-sql