When the input field to the YMDDTTMw.d informat is blank, such that the return value should be missing, it is not handling that properly.

See the Full Code tab, and in the Results tab notice the BOTH_PARTS variable for observations 1,3, and 5. The values should be missing but are not.

Operating System and Release Information

data test;                                               
  infile datalines truncover;                              
  input sub $ ldt $20.;                                  
datalines;                                               
A                                                        
A 2009-11-11:12:15                                       
B                                                        
B 2009-12-13:15:16                                       
C                                                        
;                                                        
run;        
 
data lb;                                                 
  set test;  
  input_only = input(ldt, ymddttm.);   
  if input_only ne . then dpart_only = datepart(input_only);    
  both_parts = datepart(input(ldt, ymddttm.));             
  format input_only datetime20. dpart_only both_parts yymmdd10. ; 
proc print;                                              
run;
                                                

/* Notice BOTH_PARTS should have missing values for observations 1,3,5 but doesn't */

sub          ldt                     input_only    dpart_only    both_parts

 A                                            .             .    1960-01-01
 A     2009-11-11:12:15      11NOV2009:12:15:00    2009-11-11    2009-11-11
 B                                            .             .    2009-11-11
 B     2009-12-13:15:16      13DEC2009:15:16:00    2009-12-13    2009-12-13
 C                                            .             .    2009-12-13