Sorting Table Variables by Prefix/Starting Letter - sql

Question

This is for a SAS table, so SQL commands would work, as well.
I have a table with 300 variables; they have 5 different prefixes, which I would like to sort them by. I want them in a particular order (mtr prefix before date prefix), but alphabetical would be acceptable.
I was thinking SQL would have something along the lines of:
Select mtr*, date* from Table
or
Select mtr%, date% from Table

Answer 1

As gbn says, you'll need to get the column names and dynamically build some sql (or data step code).
Here's a solution that retrieves the column names from an automatic SAS view that holds metadata about your session, ordered alphabetically, into a single macro variable which you can then use later in your code:
proc sql noprint;
select name into :orderedVarNames separated by ','
from sashelp.vcolumn
where libname='WORK' and memname='YOUR_TABLE_NAME'
order by name
;
quit;
(Obviously you'll need to replace the quoted values with the correct libname and table name for your table.) Then you can use this macro variable in another step, like this:
proc sql;
select &orderedVarNames
from YOUR_TABLE_NAME
;
quit;
Here, "&orderedVarNames" is resolved to the list of column names. You can check what is in the variable by putting it out to the log thus: %put &orderedVarNames;
There are other ways to do what you're thinking of, but this is probably the quickest and will work for any table. If you were going to use this technique for a variable list in a data step, change the separator to separated by ' '.
Once you've got the hang of this, you could then tailor the solution to get the exact order you want by generating more than one macro variable and filtering what you're retrieving from sashelp.vcolumn. Something like this:
proc sql noprint;
select name into :orderedMTRvars separated by ','
from sashelp.vcolumn
where libname='WORK' and memname='MYTABLE' and substr(name,1,3)='MTR'
order by name
;
select name into :orderedDATEvars separated by ','
from sashelp.vcolumn
where libname='WORK' and memname='MYTABLE' and substr(name,1,4)='DATE'
order by name
;
quit;
proc sql;
select &orderedMTRVars, &orderedDATEVars
from MYTABLE
;
quit;