SQL & PL/SQL

What I'm dealing with is in the GROUPS variable. It comes in from a shuttle and one of the options has a single quote in it. I'm not sure how to escape the quote inside of the variable....thanks.
Rob



create or replace FUNCTION mobile_device_support(varstart IN VARCHAR,varstop IN VARCHAR,howgroup IN VARCHAR,hastotal IN VARCHAR,devices IN VARCHAR,groups IN VARCHAR)
RETURN VARCHAR2
is
l_var VARCHAR2(32767);
s_var VARCHAR2(32767);
BEGIN
l_var := q'!SELECT NULL LINK,to_char(open_time,'YYYY-!';
l_var := l_var || howgroup;
l_var := l_var || q'!') DATIME,!';

IF hastotal = 'Y' THEN
l_var := l_var || q'!sum(decode(LOGICAL_NAME,LOGICAL_NAME,'1',0)) "TOTAL",!';
END IF;

for r1 in (
SELECT DISTINCT LOGICAL_NAME as STATE

from

SMINCREQ

where

LOGICAL_NAME LIKE '%mobile%'
ORDER BY STATE

)


LOOP
s_var :=substr(r1.state,0,29);
l_var := l_var || 'sum(decode(LOGICAL_NAME,''' || r1.state || ''',''1'',0))"' || s_var || '",';
END LOOP;
l_var := rtrim(l_var, ',');
l_var := l_var || ' FROM SMINCREQ WHERE open_time between to_date('''|| varstart ||''',''DD-MON-YYYY'') and to_date('''|| varstop ||''',''DD-MON-YYYY'') and ';
l_var := l_var || '(INSTR('':';
l_var := l_var || devices;
l_var := l_var || ':'', '':''||LOGICAL_NAME||'':'') > 0) and';
l_var := l_var || '(INSTR('':';
l_var := l_var || groups;
l_var := l_var || ':'', '':''||ASSIGNMENT||'':'') > 0)';

l_var := l_var || 'GROUP BY to_char(open_time,''YYYY-'||howgroup||''') order by to_char(open_time,''YYYY-'||howgroup||''')';
RETURN l_var;
END;