This tutorial explains how to use the COALESCE function in SAS, along with examples.

The **COALESCE **function is used to select the **first non-missing value** in a list of numeric variables. In other words, it returns the first non-blank value of each row.

*Let's create a sample dataset in SAS to understand COALESCE function.*

data temp; input ID x1-x4; cards; 1 . 89 85 . 2 79 . 74 . 3 80 82 86 85 ; run;

data want; set temp; first_non_miss =coalesce(of x1-x4); run;

If you look at the output shown in the image below, you would find **COALESCE **returns 89 in first observation which is the first non-missing value among x1= . , x2=89 , x3=85, x4 = .

**We can also use COALESCE function in PROC SQL.**

proc sql; select *,coalesce(x1,x2,x3,x4)as first_non_miss from temp; quit;

Suppose you need to calculate last non-missing value instead of first non-missing value. Unfortunately, there is no such function which returns last non-missing value. To accomplish this task, we can **reverse** a list of variables and ask SAS to calculate first non-missing value. It would be equivalent to last non-missing value. Indirectly, we are asking SAS to read variables from right to left rather than left to right.

data want; set temp; last_non_miss = coalesce(of x4-x1); run;

**Note :** coalesce(of x4-x1) is equivalent to coalesce(x4, x3, x2, x1).

In this case, COALESCE returns 85 as it is a first non-missing value (read from right to left) among x4= . , x3= 85, x2=89, x1= . .

The **COALESCEC** function is used to extract the first non-missing value from **character** variables. Whereas, the COALESCE is used for numeric variables.

can you include more helpful examples

ReplyDeleteDidnt get this

ReplyDeleteI have added more description to this article. Hope it helps!

DeletePlease add a bit more.It would be great.

ReplyDeleteexample is great

ReplyDeleteLoved the course so far. Everything is explained in a very simple & detailed way making it easier to understand. One thing I would like to add here is that coalesce can be used to replace missing values with some specific value as well.

ReplyDeleteYes we can do the same...

DeleteCOALESCE for numeric variables and COALESCEC is for character variables.

ReplyDeleteyo

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