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Proc SQL: Power of SAS SQL: • SQL looks at datasets differently from SAS – SAS looks at a dataset one record at a time, using an implied loop that moves from the first record to the last – SQL looks at all the records, as a single object • Because of this difference SQL can easily do few things that are more difficult to do in SAS • There are a number of built in functions in SQL that can be used in a select statement • Because of how SQL handles a dataset, these functions work over the entire dataset • Functions: – Count: Counts Values – Sum: Sums Values – Max: Identifies the largest value – Min: Identifies the smallest value – Mean: Averages the values Read more at www.cognigencorp.com/perspective/tipsNtricks.pub/1/PROC%20SQL%20Talk_12_.ppt – SAS SQL Introduction to Proc SQL AN INTRODUCTION TO PROC SQL® PROC SQL: When and How to Use It? Proc SQL – A Primer for SAS Programmers Understanding PROC SQL Creating Macro Variables with Proc SQL DATA Step vs. PROC SQL: What’s a neophyte to d...

Q&A: numeric variables length more than 8? We all know that the default length of the numeric variables in SAS is 8 and if suppose I want to store a number lets say (12345678910, which has a length 11 to numeric variable) to variable total, what should I do? What if the numeric variable digits are more than 12 digits and i want to store them all without any E values? ANS) The default length of numeric variables in SAS is 8 and all the numbers that we see in the sas datasets are called as floating numbers(floating point binary) and not a regular sequence numbers form 1 to 10. When we are using SAS/Windows as our operating system and then the minimum length for any numeric variable should be 3(not 1 as we get confused all the time). So if a variable contas less than 3 digits means it is stored with less space. The reason is, since a numeric variable will need a power and and the sign(+ or -), if SAS want to store a numberit defenitely needs a minimum of 3 bytes. Depending ...

VALIDVARNAME= V7 UPCASE ANY VALIDVARNAME= option is generally used in SAS whenever we want to control the SAS variable names in the dataset. VALIDVARNAME= V7 UPCASE ANY The default option will be VALIDVARNAME=V7 until we specify as UPPERCASE or ANY . When we mention options VALIDVARNAME=V7 , that means we are telling SAS to change the name of the Database column (etc EXCEL sheet column) to valid SAS name with certain rules keeping in mind. Here are those rules that SAS needs to follow, when it changes the DBMS column name to valid SAS name. Only 32 mixed case (lower or uppercase) characters are allowed in each variable. Names should be starting with an underscore or an alphabet (either uppercase or lower case character). Invalid characters in the DBMS column (ex. $) should be changed to underscores. See the SAS Language Reference: Dictionary to get more details about the rules. VALIDVARNAME=UPCASE When we mention options VALIDVARNAME=UPPERCASE we are telling SAS to change the column...

Here is the simple way of merging the data sets with a common variable if the datasets has the same prefix name. For example: col1-col10, dsn1-dsn 7 , or data1 to data10 with common variable of ID. Considering we have 10 datsets and all of them having the same prefix data; %macro mymerge (n); data merged; merge %do i = 1 % to &n; data&i %end; ; /* this additional ';' is necessary, the first ';' is for the "%end", while the second ';' is for "Merge"*/; by id; run; %mend; %mymerge(10)

Merging the data sets with a common variable if the datasets has the same prefix name? For example: col1-col10 dsn1-dsn 7 data1 to data6 with common variable of Usubjid. here is the example, I have 7 datasets i need to merge and each of them having the common variable(usubjid) to merge, and all the datasets having the same prefix dsn(dsn1 to dsn7). % macro allmerge (n); data combine ; merge %do i = 1 % to &n; dsn&i %end; ; /* this additional ';' is necessary, the first ';' is for the "%end", while the second ';' is for "Merge" */ by usubjid; run ; %mend; %allmerge (7)

Here are the 2 important questions always comes up in our minds ,(& vs && vs &&& and single dot and double dots ) when we are dealing with macros for the first time and here are the answers for them. I did find a very good regarding the above topics in the one of the SAS forums and IAN WHITLOCK explained it very clear. direct link : or when to use &,&&,and &&&,how do we distinguish? &MACVAR references a macro variable. The rule is that the scanner reads from left to right. Two ampersands resolve to one and scanner continues. If the resulting expression has ampersands then that expression is scanned again. So &&x resolves to &x resolves to value of X &&&x resolves to & followed by the value of X which then resolves to the value of the variable indicated. If you are familiar with TSO CLISTS (even if you are not), they are very similar to SAS macro. SAS was originally based on PL1, so both SAS syntax an...

We always have this question in mind, while we do the SAS programming and here is the simple answer for that, we just need to use SUM statement and the FIRST .variable in the SET statement and then the RETAIN statement to calculate the observations count per subject. By doing some minor modification we can calculate observations count per subject per visit also. (Just include visit variable in the BY variable list in PROC sort and First . variable list in datastep with SET statement). For example: data dsn ; input patid implants ; datalines; 1 3 1 1 1 2 1 1 2 1 2 2 3 1 4 2 3 1 4 5 2 3 1 6 ; run ; proc sort data=dsn ; by patid ; run ; data dsn1 ; set dsn ; by patid ; cnt+1 ; if first.patid then cnt=1 ; run ; proc sort data= dsn1 ; by patid descending cnt ; run ; data dsn2 ; set dsn1 ; by patid ; retain totcnt ; if first.patid then totcnt=cnt ; output; run; proc print data=dsn2 ; run; Output: