SAS How to set the data step to append the existing data only?

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I am writing a macro function. Some of the tables will be created if certain criteria is met. I want to append all these tables together at the end. Is there a way that I can let the function to append the existing table only?

One of the methods I can think of is let the system check if the table exist, if yes then append one by one. For example:

    %if %sysfunc(exist(table1)) %then %do; 
           data final_table; set table1; run;
    %end;
    %if %sysfunc(exist(table2)) %then %do; 
           data final_table; set table2; run;
    etc......

this will make the code really long and not effective. Is there any way to solve this? Thank you

Don't wait to the end to combine them. Build it up as you go.

You could use PROC APPEND. If the BASE table doesn't exist then it will create it. Otherwise the observations are appended.

proc append force base=final_table data=table&i;
run;

Note that this will require that the datasets have the same columns.

SAS How to set the data step to append the existing data only , Don't wait to the end to combine them. Build it up as you go. You could use PROC APPEND. If the BASE table doesn't exist then it will create it. Most SAS programmers know how to use PROC APPEND or the SET statement in DATA step to unconditionally append new observations to an existing data set. However, sometimes you need to scan the data to determine whether or not to append observations. In this situation, many SAS programmers choose one of the following methods:

Use a naming convention for your tables and store them in a single location. This would be as simple as using a consistent prefix, such as _TEMP_Table1, _temp_table2, etc.

Then when you're appending them just use the colon operator:

data want;
  set _temp_table: ;
run;

Only tables that start with that prefix will be included.

This also makes it easier to drop them all later to clean up your process.

SAS : Combining and Aggregating Data, This tutorial explains how to combine / append two data sets in SAS. It can be done with data step method, PROC SQL as well as procedure called PROC or PROC SQL UNION because it only reads in the data set being appended (i.e. the � If this data set does not exist, then SAS creates it. At the completion of PROC APPEND, the value of base-SAS-data-set becomes the current (most recently created) SAS data set. SAS-data-set-to-append . names the SAS data set that contains the observations to add to the end of the base data set.

I have come up with a solution. I post here in case anyone wants to know. I can create empty tables before running any of these tables. When I append all the intermediate tables, it they are not exist only empty table will be appended.

         data table1 table2....; stop run; /*create null tables*/

         /******/
         run the rest of the function
         /*****/

         data final_table; set table1 table2....; run; 
         /*it won't affect anything even if one of the table table&i is not created*/

COMBINING SAS DATA SETS Using SET and Proc Append, concatenate - stack data sets (place one after another) # interleave - stack data sets, but form the result In order by one or more variables present in the data sets Example 4: Merging a Single Observation with All Observations in a SAS Data Set. An observation to be merged into an existing data set can be one that is created by a SAS procedure or another DATA step. In this example, the data set AVGSALES has only one observation: data national; if _n_=1 then set avgsales; set totsales; run;

Difference Between Set Statement And Proc Append In SAS For , Append – Can say :Append to existing. Replace; Update/ Insert. Here, we are just going to explain one way only named as APPEND Some useful differences between Proc Append and Data Step SET Statement while using as Load Style� Copying or cloning an existing dataset. A data step containing only the SET statement will create an exact copy of the dataset. For example, the program. DATA new_sample; SET sample; RUN; creates a new temporary dataset called new_sample that is a clone of the already existing dataset called sample. You might use code like this when you want to

Merging Datasets - SAS Tutorials, SAS Tutorials: Merging Datasets. This SAS software tutorial shows how to stack, append, and merge datasets from a data step. Data - SAS format (*.sas7bdat) then you can combine them using the SET statement within a data step: have a one-to-one match (i.e., each subject has only one record in all� SAS-data-set-to-append . names the SAS data set that contains the observations to add to the end of the base data set. If you omit this option, then PROC APPEND adds the observations in the current SAS data set to the end of the base data set. FORCE. forces PROC APPEND to concatenate the files in some situations in which the procedure would

[PDF] Working with SAS Data Sets, enable you to edit, append, rename, or delete SAS data sets from within the SAS/ IML similarities and differences between the data set and the SAS DATA step Without a range specification, the LIST statement lists only the current� An observation to be merged into an existing data set can be one that is created by a SAS procedure or another DATA step. In this example, the data set AVGSALES has only one observation: data national; if _n_=1 then set avgsales; set totsales; run;

Comments
  • Thank you for your answer! but if the table&i does not exist, the proc append still doesn't work.
  • Why are you trying to append a table you didn't create?
  • Why not just use wildcard? set table:;