Chapter 5: Creating and

Managing Tables using PROC SQL

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© Spring 2012 Imelda Go, John Grego, Jennifer Lasecki and the University of South Carolina

Outline

Creating Tables Inserting Rows into Tables Integrity Constraints Updating Tables Altering Columns

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Creating an Empty Table

By Defining Columns By Copying Column Definitions from

another table

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Stat Lab 2012

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Client Name Client Email Client Degree USC Client Department Date Gratis Consultant

Creating an Empty Table

By Defining Columnsproc sql; create table work.lab2012(Client char(12), Email char(19), Degree char(8), USC char(1), Dept char(20), Date num format=mmddyy10. label=‘Date of First Contact’, Gratis char(1), Consultant char(10));

quit;

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Creating an Empty Table

By Defining Columns- SQL supports other data types, but

PROC SQL simply converts them to either character or numeric

- Width of CHAR column can be varied- FORMAT and LABEL is supported- proc sql; describe table work.lab2011; quit; will print the table definition to the LOG

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Creating an Empty Table

By copying the format of another table

For the Stat Lab, it would make more sense to copy columns, column labels and formats directly from a 2011 table.

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Stat Lab 2011Name Email Degree USC Dept Date Gratis Consul

tant

Joe Bridges

BridgesJ@dnr.sc.gov

External N SCDNR 12/03/2011

N John Grego

Gina White

whiteg@biol.sc.edu

Faculty Y Biology 12/05/2011

Y Wilma Sims

Matthew King

kingm3@email.sc.edu

Doctoral

Y Library& Info. Sci.

12/15/2011

Y John Grego

Wenkuan Zhao

zhaow@email.sc.edu

Faculty Y Medical School

12/16/2011

Y Wilma Sims

© Spring 2012 Imelda Go, John Grego, Jennifer Lasecki and the University of South Carolina 8

Creating an Empty Table

By copying the format of another table

proc sql; create table work.lab2012like admin.lab2011;quit;proc sql; describe table work.lab2012;quit; Columns can be specified with DROP or

KEEP

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Creating a Table from a query

We have been using the Create Table statement periodically throughout the class to save results from queries as SAS data sets

proc sql; create table sims2011 as select * from admin.lab2011 where consultant=‘Wilma Sims’;

Quit;

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Copying a Table

Convenient for moving a table from a permanent location into WORK, or vice versa

proc sql;create table work.lab2011 as select * from admin.lab2011;quit;

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Inserting Rows into a Table

Using SET Using VALUES Using a querySome of these methods will seem

terribly cumbersome, but can be useful to add a handful of new observations

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Inserting Rows into a Table

Using SETproc sql; insert into work.lab2012set client=‘Jane Lipschitz’,

email=‘lipschitzj@dnr.sc.gov, degree=‘External’, USC=‘N’, Dept=‘SCDNR’, date=‘25Jan2012’d, Gratis=‘Y’, Consultant=‘John Grego’

set client=‘Gerry Bainbridge’, email=‘bainbrid@email.sc.edu, degree=‘Faculty’, USC=‘Y’, Dept=‘School of Music’, date=‘31Jan2012’d, Gratis=‘Y’, Consultant=‘John Grego’;

select * from lab2012; quit; 13

Inserting Rows into a Table

Using VALUES- An entire set of columns can be entered

in order- A subset can be entered in a pre-

specified order

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Inserting Rows into a Table

Using VALUESproc sql; insert into work.lab2012values(‘Scott Tyler’, ’tylers@jonesctr.org’, ’External’,

’N’, ’JERC’, ’17Jan2012’d, ‘N’, ’John Grego’);select * from work.lab2012; quit;

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Inserting Rows into a Table

Using VALUESproc sql; insert into work.lab2012(Client, Consultant, Degree, USC, Date, Dept,

Gratis)values(‘Erin Merrick’, ’Wilma Sims’, ’Masters’, ’Y’,

’07Jan2012’d, ’Environment’, ‘N’);select * from work.lab2012; quit;

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Inserting Rows into a Table

Using a queryproc sql; insert into work.lab2012select * from admin.lab2011 where

month(date)=12;select * from work.lab2012; quit;

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Integrity Constraints

Restrict data values that can be assigned to columns

General Integrity Constraints– CHECK– NOT NULL– UNIQUE– PRIMARY KEY (NOT NULL and UNIQUE)

Integrity Constraints

proc sql; create table work.lab2012(Client char(12) primary key, Email char(19), Degree char(8), USC char(1) check(USC in (‘N’ ’Y’ ’y’ ’n’), Dept char(20), Date num format=mmddyy10. check(date between ’01Jan2012’d and ’31Dec2012’d), Gratis char(1), Consultant char(10) check(Consultant in (‘John Grego’,’Wilma Sims’));

quit;

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Integrity Constraints Constraints can be viewed with the DESCRIBE

TABLE CONSTRAINTS statement:

proc sql;describe table constraints work.lab2012;quit;

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Integrity Constraintsproc sql; insert into work.lab2012values(‘Erin

Merrick’,’merrickj@email.sc.edu’ ,’Masters’, ’Y’, ‘Environment’,’07Jan2011’d,’Y’,’Wilma Sim’)

values(‘Scott Tyler’, ’tylers@jonesctr.org’, ’External’, ’No’, ’JERC’, ’17Jan2012’d, ‘N’, ’John Grego’)

values(‘Erin Merrick’, ‘Masters’,’Y’, ‘Environment’, ’01Feb2012’d, ‘N’, ’Wilma Sims’) ;

quit;

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Integrity Constraints A separate CONSTRAINT statement can also be

used to handle integrity constraints Names are assigned to the constraints

proc sql; create table work.lab2012(Client char(12) primary key, Email char(19), Degree char(8), USC char(1) Dept char(20), Date num format=mmddyy10., Gratis char(1), Consultant char(10), constraint Check_USC check(USC in (‘N’ ’Y’ ’y’ ’n’)) );

quit;22

Integrity Constraints By default, SAS will not accept any additional

rows once it finds an error Options for UNDO_POLICY

– REQUIRED (the record is not added)– NONE (the record is skipped)– OPTIONAL (hybrid that inserts records when possible)

Table constraints can be viewed using DESCRIBE

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Updating Tables

Updating Existing Rows– With a common expression– With a conditional expression (similar to

IFELSE construction)

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Updating Tables

Use the SET expression to modify values

The WHERE clause can make the change conditional

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Updating Tables-Example

proc sql; create table lab2012pay likeadmin.lab2011pay;quit;

proc sql; update lab2012pay set rate=rate*1.05; quit;

proc sql; update lab2012pay set rate=rate*1.0013 where consultant='Director'; quit;

Updating Tables

Use the SET expression with a CASE clause for conditional changes to a variable

The use of CASE will be very familiar to those who have used IFELSE in either R or Excel

CASE can be used elsewhere in a PROC SQL clause

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Updating Tables-Example

proc sql;update lab2012set rate=rate*casewhen consultant=‘Director’ then 1.05when consultant=‘Manager’ then 1.0375else 1.045end;

Updating Tables

The update can be modified for greater efficiency

proc sql;update lab2012set rate=rate*case consultantwhen ‘Director’ then 1.05when ‘Manager’ then 1.0375else 1.045end;

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Updating Tables

DELETE FROM can be used to eliminate rows:

proc sql;delete from lab2012where date lt ’01Jan2012’d;quit;

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Updating Tables

ALTER TABLE can be used to update columns.

Options can be entered separately or simultaneously– ADD– MODIFY– DELETE

MODIFY cannot change a column’s name

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Updating Tables-Example

proc sql;alter table lab2012add College char(20) label=‘College or School’, time format=hour4.1

modify date format=weekdate31.quit;

Updating Tables

DROP TABLE can be used to delete a table

proc sql;drop table admin.lab2011;quit;

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