<hs AT dc-sug DOT org ("Howard Schreier)> wrote in message news:200808050121.m74Ilim5019094@malibu.cc.uga.edu... > On Tue, 5 Aug 2008 00:40:09 GMT, Lou <lpogoda@VERIZON.NET> wrote: > > ><hs AT dc-sug DOT org ("Howard Schreier)> wrote in message > >news:200808040153.m73AlDCD015752@malibu.cc.uga.edu...

> >> PROC SQL claims to be able to do this. To illustrate: > >> > >> proc sql; > >> create table demo as > >> select * > >> from sashelp.class; > >> alter table demo > >> drop age, weight; > >> quit; > >> > >> Log shows: > >> > >> NOTE: Table WORK.DEMO has been modified, with 3 columns. > >> > >> However, evidence indicates that behind the scenes PROC SQL transcribes > >the > >> body of the table, so you will end up incurring the cost of re-creating. > > > >PROC SQL makes no such claim > > The first sentence of the doc page for ALTER says "Adds columns to, drops > columns from, and changes column attributes in an existing table." > (http://tinyurl.com/56qm6p or > http://support.sas.com/onlinedoc/913/getDoc/en/proc.hlp/a002473671.htm).

Well, I guess you could construe that sentence to mean it drops columns from a table "in place", that is without rewriting the entire dataset. However, you could make the same statement about the following DATA step (as far as dropping a column is concerned at any rate)"

DATA FEE (DROP = FIE); SET FEE; RUN;

Neither the DATA step nor PROC SQL appear to get rid of a column without rewriting the table/dataset. If you make your test table/dataset large enough that the process takes a minute or three, you can open a Windows Explorer window on the library containing the file and by clicking on View>Refresh a few times, watch it happening.