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SAS Functions [2-14]

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SUM Functions

Var3=SUM(of Var1, Var2);

The SUM function allows you to add up values despite the present of missing values.

In SAS, there are two ways to add up numeric values: 

1. Plus Sign (+) or
2. SUM function

The usage of the Plus Sign (+) has been demonstrated in the previous session.

The downside of using the Plus Sign (+) is that the summation will not be performed with the present of missing values.

Let's illustrate this with an example.

Data Numbers; Input Val0 Val1 Val2; Datalines; 4 1 26 1 4 49 9 . 45 23 13 . 48 11 22 . 34 43 19 25 25 7 0 . 17 10 23 16 23 33 ; Run;

The NUMBERS data set above contains 3 variables: Val0, Val1 and Val2. 

[Note: To see the NUMBERS data set on SAS Studio, run the code in the yellow box above]

Some values from the data set are clearly missing.

Now, we're going to add up all 3 variables using the Plus Sign (+). 

Example

Data Math1;
    Set Numbers;
    val3 = val0+val1+val2;
Run;

The numbers were not added up when there are missing values!

This is not good, as you could potentially lose tons of data because of the present of just 1 missing value!

The better way to add up values is to use the SUM function.

Example

Data Math2;
    Set Numbers;
    Val3 = Sum(of val0, val1, val2);
Run;

The SUM function will ignore any missing values when adding up the numbers.

No data will be lost due to missing values.


Function Structure

The SUM function is structured as:

Sum(of val1, val2, ...);

You can have as many parameters in the SUM function as you want.

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Exercise

Copy and run the SALES data set from the yellow box below.

Data Sales; Input StoreID $ Mon Tue Wed Thr Fri; Datalines; STR001 890 750 760 950 1150 STR002 650 450 520 760 970 STR003 1420 1250 1300 1425 1890 STR004 830 . 710 810 1040 STR005 760 550 780 980 1230 STR006 430 530 560 . 970 STR007 1010 980 . 890 1230 STR008 440 740 560 640 740 STR009 670 690 730 950 870 STR0010 570 790 820 810 640 ; Run;

SALES contains 6 variables:

• STOREID
  
• MON: SALES (Monday)
• TUE: SALES (Tuesday)
• WED: SALES (Wednesday)
• THR: SALES (Thursday)
• FRI: SALES (Friday)

Write a SAS program to calculate the total sales of the week. Create any data set or variables if necessary.

Next

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