The Top 60 SAS Interview Questions You Need to Know in 2023

Getting ready for a SAS interview? With SAS skills in high demand you want to be as prepared as possible. Knowing the right answers to common SAS interview questions can help you stand out from other candidates.

In this comprehensive guide, I’ll cover the top 60 SAS interview questions with detailed explanations and examples From basics about SAS to tricky SQL and macro questions, these interview questions highlight what hiring managers actually ask

Whether you’re a beginner or an experienced SAS programmer this guide will boost your confidence for that upcoming SAS interview. Let’s dive in!

Overview of Common SAS Interview Questions

SAS interview questions often focus on testing your hands-on programming skills. However, interviewers also want to assess your conceptual knowledge of SAS.

Here’s a quick overview of common SAS interview question topics:

• SAS programming basics – Questions about reading raw data, DATA step, merging datasets, WHERE vs IF, arrays, loops, functions like SUM, MEAN, etc.

• Data cleaning and manipulation – Using functions for data cleaning, subsetting, sorting, removing duplicates, merging datasets, and more.

• SAS procedures – SQL, REPORT, FREQ, MEANS, SUMMARY, SORT, etc. Know how and when to use them.

• Macro programming – Creating macro variables, debugging macros, %SYSFUNC vs %QSYSFUNC, macro loops, macro parameters.

• SAS output – ODS, PROC PRINT, exporting datasets, changing destination of LOG and OUTPUT windows.

• Performance tuning – Comparing data step and PROC SQL, optimizing code with WHERE vs subsetting later, knowing when to use indexes.

This covers the most common SAS topics for interviews. Let’s look at specific questions now.

Frequently Asked SAS Interview Questions and Answers

Here are detailed explanations for the top 60 SAS interview questions:

1. How do you import an Excel file into SAS?

Use the FILENAME and INFILE statements:

FILENAME excel "/folders/myfolders/excel.xlsx";DATA dataset;   INFILE excel;   INPUT var1 var2 var3;RUN;

FILENAME associates a FILEREF (excel) with the Excel file path. INFILE uses that FILEREF to read the file. INPUT names and defines the variables.

2. What is the difference between the WHERE and IF statements?

• WHERE subsets data before the DATA step executes. This improves efficiency.

• IF subsets data after the DATA step executes. WHERE is usually better for performance.

• WHERE can be used in PROC SQL but IF cannot.

• Multiple IF statements can be used, but only one WHERE.

3. How do you merge two SAS datasets?

Use a SET + MERGE statement:

DATA merged;   MERGE dataset1 dataset2;   BY ID; RUN;

This performs a match-merge, combining dataset1 and dataset2 rows with the same ID value.

4. What are the different types of joins in PROC SQL?

• INNER JOIN – Returns only matching rows in both tables.

• LEFT JOIN – Returns all rows from left table plus matched rows from right table

• RIGHT JOIN – Returns all rows from right table plus matched rows from left table.

• FULL JOIN – Returns all rows from both tables, with NULLs if no match.

5. How do you sort a dataset in descending order?

Use PROC SORT with the DESCENDING option:

PROC SORT DATA=mydata OUT=sorted;   BY DESCENDING score;RUN;

This sorts mydata by score in descending order, outputting to sorted.

6. What is a SAS macro? Give an example.

A SAS macro enables reusable code. Defines code once, then execute repeatedly with different parameters.

Example:

%MACRO meancustom(dsn,var);   PROC MEANS DATA=&dsn N MEAN;      VAR &var;   RUN;%MEND;%meancustom(iris,petal_length); 

This macro calculates mean for any dataset and variable.

7. How do you debug a SAS macro?

Debugging options:

• SYMBOLGEN – Shows macro variable resolution

• MPRINT – Prints SAS code generated by macro statements

• MLOGIC – Prints macro execution logic

• %PUT – Prints custom debug messages

8. What is a SAS array? Give an example.

A SAS array groups variables under a single name for easier processing. For example:

DATA dataset;   ARRAY values{3} value1-value3;   DO i = 1 TO 3;      values{i} = i;    END;RUN;

This loops through the array, assigning value1=1, value2=2, value3=3.

9. What is the difference between %SYSFUNC and %QSYSFUNC?

• %SYSFUNC resolves the function first, then resolves the macro expression.

• %QSYSFUNC resolves the macro expression first, then applies the function.

So surround macro expressions with %QSYSFUNC for intended resolution.

10. How do you transpose or pivot data in SAS?

Use PROC TRANSPOSE:

PROC TRANSPOSE DATA=dataset OUT=transpose;   BY id;   VAR value1-value10; RUN;

This will transpose value columns into rows for each ID.

11. What is a SAS format? Give an example.

Formats present data values in a more readable way without modifying the underlying data.

PROC FORMAT;   VALUE agefmt       20-40 = "20s"      41-60 = "40s"   ;RUN;DATA dataset;   AGE = 35;   FORMAT age agefmt.;RUN;

Now AGE displays as 20s instead of 35.

12. How can you export a SAS dataset to Excel?

Use PROC EXPORT:

PROC EXPORT DATA=dataset             OUTFILE="/folders/myfolders/output.xlsx"              DBMS=XLSX;RUN;

This exports dataset to an Excel file.

13. What is the difference between length and informat in SAS?

• LENGTH allocates storage space for a variable.

• INFORMAT specifies how to read and interpret raw data for input.

So LENGTH is for storage, while INFORMAT is for input.

14. You have a variable Q1 scored 1-5. How do you count responses of 1, 2, 3, 4, and 5?

Use PROC FREQ:

PROC FREQ DATA=dataset;   TABLES Q1 / OUT=counts;RUN;

This outputs a dataset “counts” containing counts for each level of Q1.

15. How do you input the current date in a SAS program?

Use the TODAY() function:

DATA dataset;   date = TODAY();RUN;

TODAY() will set date to today’s date.

16. How can you read data from a raw text file in SAS?

Use INFILE and INPUT statements:

FILENAME txtfile "/folders/myfolders/file.txt";DATA dataset;  INFILE txtfile;  INPUT var1 $ var2 var3;RUN;

This reads the text file, defining var1 as character and var2/var3 as numeric.

17. What is a SAS libname? Give an example.

A libname assigns a shortcut name to reference a library path.

LIBNAME myfolders "/folders/myfolders";PROC PRINT DATA=myfolders.dataset; RUN;

Now we can reference files using the libname.

18. What is the difference between a VAR statement and an ARRAY statement?

• VAR lists variables for procedures like MEANS, PRINT, FREQ, etc.

• ARRAY declares an array to process variables as a group in the DATA step.

19. How can you add a new variable to a dataset in SAS?

In the DATA step, define and calculate the new variable:

DATA dataset;  SET dataset;    new_var = /* calculation */; RUN;

This adds new_var to dataset, defining it within the DATA step.

20. You have age categories 20-29, 30-39, etc. How do you print the categories instead of age values?

Use a FORMAT:

PROC FORMAT;  VALUE agecat     20-29 = "20s"    30-39 = "30s"  ;RUN;DATA dataset;  AGE = 32;  FORMAT age agecat.;RUN;