Merging with standard IDs

[newsas007]

Hi all,

I have several data sets i am trying to merge using a standard dataset that contains IDs i need for the final merge. Here is an example: dataset A and dataset B need to be merged. Dataset C is the 'standard' dataset that has just ID #s that i need in the final merge.  Also, is it better to use SQL or just data step? Thanks

Dataset A

ID	var1	var2
2	Cat1	2
3	cat2	4
4	Cat1	6
6	cat2	8
7	Cat1	0
9	cat2	10
10	cat1	12

Dataset B

ID	Var3
1	1.5
2	3.6
3	5.3
5	7.9
7	9.2
9	2.5
10	2.9

Dataset C

ID

2

3

4

7

9

10

Data want

ID	var1	var2	Var3
2	Cat1	2	3.6
3	cat2	4	5.3
4	Cat1	6
7	Cat1	0	9.2
9	cat2	10	2.5
10	cat1	12	2.9

[Kurt_Bremser]

Since the datasets are already sorted, and have a 1:1 relationship throughout, the data step is the method of choice:

data want;
merge
  a
  b
  c (in=in_c)
;
by id;
if in_c;
run;

[newsas007]

Thank you!

[novinosrin]

data a;
input ID	var1 $	var2;
cards;
2	Cat1	2
3	cat2	4
4	Cat1	6
6	cat2	8
7	Cat1	0
9	cat2	10
10	cat1	12
;


 

data B;
input ID	Var3;
cards;
1	1.5
2	3.6
3	5.3
5	7.9
7	9.2
9	2.5
10	2.9
;
 

data C;
input ID;
cards;
2
3
4
7
9
10
;

data want;
merge c(in=c) a b;
by id;
if c;
run;

[newsas007]

This is great! Thanks a lot!
Just in case i had to select variables, would it be better to use SQL?

[novinosrin]

Yes, you could use SQL Select or datastep keep/drop dataset options. The choice is yours.

Sir @Kurt_Bremser / @Tom  or @Reeza  can offer better slick advice if your question is related to "performance". 

[Kurt_Bremser]

You can use KEEP and DROP statements, or KEEP= and DROP= dataset options.