what does the D mean?

[tianerhu]

What does the upperletter D mean  ? and why is the code wrong? Thank you.

[PaigeMiller]

The D indicates that SAS will convert the value inside the double-quotes to a valid SAS date. SAS dates are integers, representing the number of days since 01JAN1960, so the correct value is 0 (if there are no syntax errors). Had the code read

x="01JAN2020"d;

the value would be 21915, the number of days since 01JAN1960.

[tianerhu]

Thank you.

[Reeza]

It's a "constant" (could have sworn it was once called literal) and tells SAS to interpret the data in quotes as a date. 

Some of the other options you may see:

DT -> Datetime

T -> Time

N -> Variable or data set name

This also means if you add code right after the end of the quotation marks you can sometimes get a message about the behaviour of a variable after a quote changing over time. 

Characters That Follow a Character Constant	Possible Interpretations	Examples
b	bit testing constant	'00100000'b
d	date constant	'01jan04'd
dt	datetime constant	'18jan2005:9:27:05am'dt
n	name literal	'My Table'n
t	time constant	'9:25:19pm't
x	hexadecimal notation	'534153'x

https://documentation.sas.com/?cdcId=pgmsascdc&cdcVersion=9.4_3.5&docsetId=lrcon&docsetTarget=p0cq7f...

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@tianerhu wrote:

What does the upperletter D mean  ? and why is the code wrong? Thank you.

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[tianerhu]

[ballardw · Accepted solution]

With pictures it is hard to tell but it appears to me that there is a space between the " and the D

Examine the lines below:

"01JAN1960" D
"01JAN1960"D

The first would be an error, the second is a date literal. Date literal is the way that you tell SAS you want to use the internal numeric representation of a date (or datetime or time value). The D could be lower case as could the month abbreviation. But there cannot be a space between the quote and the letter.

Example log from running code involving those two lines:

58   data junk;
59      x="01JAN1960" D;
                      -
                      22
ERROR 22-322: Syntax error, expecting one of the following: !, !!, &, *, **, +, -, /, <, <=, <>,
              =, >, ><, >=, AND, EQ, GE, GT, IN, LE, LT, MAX, MIN, NE, NG, NL, NOTIN, OR, ^=, |,
              ||, ~=.

60   run;

NOTE: Character values have been converted to numeric values at the places given by:
      (Line):(Column).
      59:6
NOTE: The SAS System stopped processing this step because of errors.
WARNING: The data set WORK.JUNK may be incomplete.  When this step was stopped there were 0
         observations and 2 variables.
NOTE: DATA statement used (Total process time):
      real time           0.00 seconds
      cpu time            0.01 seconds


61
62   data junk2;
63      x="01JAN1960"D;
64   run;

NOTE: The data set WORK.JUNK2 has 1 observations and 1 variables.
NOTE: DATA statement used (Total process time):
      real time           0.00 seconds
      cpu time            0.00 seconds

The underscore under the letter D in the first bit is "unexpected" because of the space.

Pictures of proportional font text can be hard to tell but I think that is the issue in this case.

If you copy and run my code you will find the value of X in the Junk2 data set is indeed 0. 1 January 1960 is the base numeric value for dates and is day "zero".

[tianerhu]

Thank you .