SAS Language

Write idiomatic, production-quality SAS code. This skill covers the SAS language itself, independent of any framework.

Scope

DATA step programming (SET/MERGE/BY, RETAIN, arrays, DO loops, hash objects, first./last. processing)
PROC SQL (joins, subqueries, views, pass-through with CONNECT TO)
Macro language (%macro/%mend, macro variables, %local/%global, conditional %IF logic, quoting functions %STR/%NRSTR/%BQUOTE, CALL SYMPUTX)
Common PROCs: SORT, MEANS/SUMMARY, FREQ, TRANSPOSE, REPORT, PRINT, CONTENTS, DATASETS, FORMAT, IMPORT/EXPORT
Formats and informats (user-defined via PROC FORMAT, picture formats)
ODS output (HTML, PDF, RTF, Excel, OUTPUT destination)
File I/O: LIBNAME, FILENAME, INFILE/INPUT, FILE/PUT

Non-negotiable: no WARNINGs

Generated SAS code must run cleanly — zero WARNINGs (and zero ERRORs) in the log. Treat every

WARNING:

as a defect: uninitialized variables, implicit type conversions, truncation notes that should be warnings, "no observations", unresolved macro references, etc. If a warning is truly unavoidable, suppress it deliberately (e.g. an explicit option) and comment why. Likewise avoid superfluous NOTEs where reasonable.

Style rules

These follow the @sasjs/core coding standards — apply them to all SAS code:

One statement per line; indentation = 2 spaces, no tabs, no trailing whitespace
Lines no longer than 80 characters; unix (LF) line endings; UTF-8
Avoid non-ASCII / special characters entirely — maximum compatibility across SAS installations and encodings
Always end steps with
```
run;
```
; for
```
proc sql
```
(and CAS-connected procs)
```
quit;
```
is essential to avoid
```
WARNING: You cannot disconnect or terminate session ...
```
on Viya
All dataset references must be 2-level (
```
work.blah
```
, not
```
blah
```
) — protects against
```
DATASTMTCHK=ALLKEYWORDS
```
and an active
```
USER
```
library
Explicit
```
length
```
/
```
attrib
```
for character variables rather than relying on defaults (avoids implicit length=8 truncation)
Use literal suffixes for clarity (
```
'01JAN2020'd
```
,
```
'12:30't
```
)
Prefer
```
proc sort
```
with
```
nodupkey
```
over manual dedup logic
Macros:
- Define with parentheses, even with no parameters:
```
%macro x();
```
  not
```
%macro x;
```
- Closing
```
%mend;
```
  must repeat the macro name
- Macro calls are not terminated with a semicolon:
```
%my_macro()
```
  not
```
%my_macro();
```
- Mandatory parameters positional; optional parameters keyword (
```
var=
```
  ) style
- Macro names lowercase, verb-noun convention
- Macro variables without trailing dot (
```
&var
```
  not
```
&var.
```
  ) unless needed to prevent incorrect resolution
- ALL macro variables must be
```
%local
```
  unless deliberately global (globals should use an application prefix to avoid collisions); use
```
call symputx
```
  (not
```
symput
```
  ) in DATA steps
- Comment with
```
/* */
```
  inside macros (asterisk comments are compiled into the macro)
- Guard macro logic with
```
%length(&var)=0
```
  checks rather than
```
&var=
```
  (empty comparisons are unsafe)
Avoid naming collisions: use
```
%sysfunc
```
-/
```
&syslast
```
-based work tables (e.g.
```
data &output; set &syslast; run;
```
) rather than hard-coded names

Portability awareness

Note when code differs between SAS 9.4 and Viya (e.g. CAS actions vs procs,
```
proc casutil
```
for sashdat loading, no X command on locked-down servers)
Avoid hard-coded physical paths and engine-specific options unless asked

Common pitfalls to flag when reviewing

Unintended many-to-many MERGEs
Automatic variable
```
_ERROR_
```
/ implicit RETAIN surprises
Macro timing issues: referencing
```
&macrovar
```
before it exists,
```
%if
```
evaluating data-step variables (use
```
if
```
/
```
symget
```
instead)

Automatic macro variables (

&syscc

&syswarningtext

&syserrortext

&sysdate

&sysuserid

, etc.) are READ-ONLY — attempting to overwrite them (e.g.

%let syswarningtext=;

call symput('syscc',...)

) raises

ERROR: Unable to assign value to a macro variable that is read only

(or similar). Never try to "clear" them.

Truncation from implicit length=8 on first assignment
```
proc sql
```
cartesian product warnings

sas

NPX Install

Tags

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