Introduction

Combining data horizontally refers to the process of merging or joining multiple data sets into one data set. This process is referred to as a horizontal combination because in the final data set, each observation (or horizontal row) will have variables from more than one input data set.


Combining data sets horizontally


It is useful to combine data horizontally if you have several data sets that contain different but related information. For example, suppose you have one data set that contains employee data with the variables IDNumber, Name, and Address, and another data set that contains employee data with the variables IDNumber and Salary. You can combine the data from these two input data sets horizontally to create an output data set that contains IDNumber, Name, Address, and Salary.

There are several methods for combining data horizontally. This lesson focuses on several methods of combining data horizontally in the DATA step, and compares a DATA step match-merge with a PROC SQL join. This lesson also covers several techniques for horizontally combining data from an input data set with values that are not stored in a SAS data set.


1.5 hours



In this lesson, you learn to

  • identify factors that affect which technique is most appropriate for combining data horizontally
  • use the IF-THEN/ELSE statement, SAS arrays, or user-defined SAS formats to combine data horizontally
  • use the DATA step with the MERGE statement to combine data sets that don't have a common variable
  • use the SQL procedure to combine data sets that don't have a common variable
  • identify the differences between the DATA step match-merge and the PROC SQL join
  • create an output data set that contains summary statistics from PROC MEANS
  • combine summary statistics in a data set with a detail data set
  • calculate summary data and combine it with detail data within one DATA step
  • use the SET statement with the KEY= option to combine two SAS data sets
  • use an index to combine two data sets
  • use _IORC_ to determine whether an index search was successful.

complete the following lessons:

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