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**SAS Functions [2-14]**

**SUM Functions**

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:

- Plus Sign (+) or
**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

Let's illustrate this with an example.

__will not be performed__with the present of missing values.Let's illustrate this with an example.

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.

**Exercise**

Copy and run the

**SALES**data set from the yellow box below.

**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.

*Need some help?*

**HINT: **

The plus sign (+) will not work when there is missing value.

**SOLUTION: **

Data Sales_Week;

Set Sales;

Total = Sum(of Mon, Tue, Wed, Thr, Fri);

Run;

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