Preparing Data for Match-Merging (2)

Merging SAS Data Sets

Preparing Data for Match-Merging

Sorting Data

If your data is not appropriately sorted or indexed, you can use the SORT procedure before match-merging. You can sort the existing data set permanently or create a separate, sorted output data set.

General form, simple PROC SORT step:

PROC SORT <DATA=SAS-data-set>

<OUT=SAS-data-set>;

BY variable(s);

RUN;

where

the DATA= option names the data set to be read
the OUT= option creates an output data set containing the data in sorted order
variable(s) in the required BY statement specifies the variable(s) whose values are used to order the data.

If you don't use the OUT= option, PROC SORT permanently sorts the data set specified in the DATA= option. If you need your data sorted to produce output for only one SAS session, you should specify a temporary SAS data set as the output data set.

In the PROC SORT steps below, the two data sets are sorted by the common variable ID so that data is merged correctly for each patient.

     proc sort data=clinic.demog;
        by id;
     run;
     proc sort data=clinic.visit;
        by id;
     run;
     proc print data=clinic.demog;
     run;
     proc print data=clinic.visit;
     run;

Obs ID Age Sex Date

1 A001 21 m 05/22/75

2 A002 32 m 06/15/63

3 A003 24 f 08/17/72

4 A004 . 03/27/69

5 A005 44 f 02/24/52

6 A007 39 m 11/11/57

Obs	ID	Age	Sex	Date
1	A001	21	m	05/22/75
2	A002	32	m	06/15/63
3	A003	24	f	08/17/72
4	A004	.		03/27/69
5	A005	44	f	02/24/52
6	A007	39	m	11/11/57

Obs ID Visit SysBP DiasBP Weight Date

1 A001 1 140 85 195 11/05/98

2 A001 2 138 90 198 10/13/98

3 A001 3 145 95 200 07/04/98

4 A002 1 121 75 168 04/14/98

5 A003 1 118 68 125 08/12/98

6 A003 2 112 65 123 08/21/98

7 A004 1 143 86 204 03/30/98

8 A005 1 132 76 174 02/27/98

9 A005 2 132 78 175 07/11/98

10 A005 3 134 78 176 04/16/98

11 A008 1 126 80 182 05/22/98

Obs	ID	Visit	SysBP	DiasBP	Weight	Date
1	A001	1	140	85	195	11/05/98
2	A001	2	138	90	198	10/13/98
3	A001	3	145	95	200	07/04/98
4	A002	1	121	75	168	04/14/98
5	A003	1	118	68	125	08/12/98
6	A003	2	112	65	123	08/21/98
7	A004	1	143	86	204	03/30/98
8	A005	1	132	76	174	02/27/98
9	A005	2	132	78	175	07/11/98
10	A005	3	134	78	176	04/16/98
11	A008	1	126	80	182	05/22/98