Data update sas

Missing values are indicated by. If a transaction data set has multiple observations with the same primary identification key, they will be sequentially updated. Note that Miller and Bush look different from those in the above example. The last observation of the transact data set was added, although it has the same id 02 as Miller. This is document aljg in the Knowledge Base. Last modified on Showing results for.

Search instead for. Did you mean:. All forum topics Previous Next. Go to Solution. Data Step Update Statement. Posted PM views. Tags: data step. Accepted Solutions. Re: Data Step Update Statement. First and foremost, the Update Statement deals with exactly two data sets. On the other hand, the Merge can handle as much as data sets. Also, a By Statement must follow the Update Statement immediately. That is not the case with the Merge Statement. Besides the two differences above, there are two fundamental differences in the way the the two statements processes data.

Namely how they process multiple observations in by groups. And how they deal with missing values. As you have seen, the MergeWant data set contains two observations more than the Wand data set. This is due to the way that the two statements process multiple observations in the same By-Group. With an Update, SAS does not write an updated observation to the new data set until it has applied all the transactions in a BY group.

However, with the Merge Statement, SAS outputs as many observations for each By-Group as the number of observations in the By-Group with the highest number of observations. While Want contains only 1. Furthermore, the Update Statement does not overwrite observations with missing values by default. However, the Merge does.