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How do I convert a date stored as string into a SAS datetime with proc sql?

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Occasional Contributor
Posts: 18

How do I convert a date stored as string into a SAS datetime with proc sql?

If I have a value like YYYYMMDD stored as string (for example 20170123), how can I convert it to SAS datettime?

 

thanks

Super User
Posts: 5,518

Re: How do I convert a date stored as string into a SAS datetime with proc sql?

If it's a string,  you will need to assign the date value to a new variable since SAS stores dates as numeric:

 

newvar = input(stringvar, yymmdd8.);

 

If you actually have separators in your string, such as yyyy/mm/dd you will need to expand the width:

 

newvar = input(stringvar, yymmdd10.);

 

This gives you a SAS date (not a datetime).  While you can convert this to a datetime value, it's not clear why you would want to do that.  You don't actually have any measurement of hours, minutes, or seconds in your data.

 

Occasional Contributor
Posts: 18

Re: How do I convert a date stored as string into a SAS datetime with proc sql?

Posted in reply to Astounding

Thank you, the reason I want to convert to datetime is because I'm learning how to handle both SAS date and datetime formats Smiley Happy

Super User
Posts: 11,343

Re: How do I convert a date stored as string into a SAS datetime with proc sql?

Don't forget to assign a format to the variable so you can see the date value instead of the internal numeric stored value.

 

If you have a date and time parts the function DHMS will create a datetime variable:

 

DT = dhms(date, hours, minutes, seconds);

If you don't have any time values you can set a default such as

DT = dhms(date,0,0,0); which would be midnight at the start of the day.

Super Contributor
Posts: 474

Re: How do I convert a date stored as string into a SAS datetime with proc sql?

Also usually...

 

SAS Date values are stored as the number of days since 1960/01/01

SAS Time values are stored as the number of  seconds since midnight

SAS Datetime values are stored as the number of seconds since 1960/01/01

 

Knowing that, you can easily switch between Date, Datetime and time values just by doing some maths:

 

DATETIME = DATE*(24*60*60) 

DATE = int(DATETIME/(24*60*60)) 

TIME = mod(DATETIME,24*60*60)

 

Or you could use the dedicated functions:

 

Datepart, that will return the Date value of it's Datetime value argument

Timepart, that will return the Time vale of it's Datetime value argument

DHMS, that will return the Datetime value of it's Date value argument (+ the hour, minute and second specified)

 

More on Date, Datime and Time values here:

 

http://support.sas.com/documentation/cdl/en/lrcon/62955/HTML/default/viewer.htm#a002200738.htm

 

Hope it helps.

 

Daniel Santos @ www.cgd.pt

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