1. An Introduction to SQL

2. Structured Query Language
Structured Query Language (SQL) is a standardized language originally designed as a relational database query tool. SQL is currently used in software products to retrieve and update data.

3. Structured Query Language: Timeline
1970
1980
1990
2000
IBM develops SQL.
1970 – Dr. E. F. Codd of IBM proposes SQL.
1981 – First commercial SQL product is released.
1989 – More than 75 SQL-based systems exist. SAS 6.06 includes PROC SQL.
1999 – PROC SQL is enhanced for SAS 8.
2004 – PROC SQL is enhanced for SAS®9.

4. The SQL Procedure
Enables the use of SQL in SAS Part of Base SAS Follows American National Standards Institute (ANSI) standards Includes enhancements for compatibility with SAS software

5. PROC SQL Features

6. Query SAS data sets proc sql ; select * from orion.employee_payroll
having salary=max(salary) ;
quit;

7. Generate reports from SAS data sets
proc sql ;
select mean(salary) "Average Salary" format=dollar12., employee_gender
from orion.employee_payroll
group by employee_gender ;
quit;

8. Combine SAS data sets in many ways
Inner Joins
Full
Right
Left
Outer Joins

9. Inner joins
Return only matching rows Maximum of 256 tables can be joined at the same time.

10. Outer Joins
Return all matching rows, plus nonmatching rows from one or both tables Can be performed on only two tables or views at a time.
Left
Full
Right

11. Create and delete SAS data sets, views, and indexes
proc sql ;
create table newbp as
select mean(BPXSY1,BPXSY2,BPXSY3,BPXSY4) as mnsbp,
mean(BPXDI1,BPXDI2,BPXDI3,BPXDI4) as mndbp,
seqn
from nh9.bloodpressure ;
select n(mnsbp) "mnsbp",n(mndbp) "mndbp"
from newbp
quit;

12. Update existing SAS data sets
data tmp;
input x b $
datalines;
1 a1 1 a2 2 b1 2 b2 4 d ;
proc print data=tmp;
title "tmp";
run;
title;
proc sql;
update tmp
set x=x*2
where b contains "a";
select * from tmp;
quit;

13. Access Meta Data proc sql ; select memname,name,label
from dictionary.columns
where libname="FRAM" and
upcase(label) contains "CHOL";
quit;

14. Create Macro Variables
proc sql ;
select mean(age) into : mnage
from fram.framexam5subset ;
quit;
%put Average age: &mnage;

15. (Sometimes) reproduce the results of multiple DATA and procedure steps with a single query
proc sql;
create table analysis as
select a.seqn,mortstat=1 as dead,permth_exm,
mean(BPXSY1,BPXSY2,BPXSY3,BPXSY4) as mnsbp,
mean(BPXDI1,BPXDI2,BPXDI3,BPXDI4) as mndbp,
riagendr=1 as male,
ridageyr as age,
ridreth2 as race_ethn,
lbdhdl as hdl,
lbxtc as chol,
bmxbmi as bmi
from nh9.mortality(keep=seqn eligstat mortstat permth_exm) a,
nh9.bloodpressure(keep=seqn bpxsy1-bpxsy4 BPXDI1-BPXDI4) b,
nh9.demographics (keep=seqn ridageyr riagendr RIDRETH2) c,
nh9.bodymeasurements(keep=seqn bmxbmi) d,
nh9.cholesterolhdl(keep= seqn LBDHDL LBXTC) e
where eligstat eq 1 and
a.seqn=b.seqn and
b.seqn=c.seqn and
c.seqn=d.seqn and
d.seqn=e.seqn
order by seqn ;
quit;
Example from Create Nhanes1999 Analytic File, 11 data/sort steps replaced by one sql

16. Structured Query Language
Input
Output
SAS Data Set
Report
PROC SQL
PROC
SQL
DBMS Table
SAS Data Set
SAS Data View
SAS Data View
DBMS Table

17. Terminology Data Processing SAS SQL File Data Set Table Record
Observation
Row
Field
Variable
Column

18. The SQL Procedure
Tool for querying data Tool for data manipulation and management An augmentation to the DATA step not A DATA step replacement