I now know how to find yesterdays date, however, I get an error message stating that the operands (PROCESS_DT and DATE_STAMP) are not compatible. PROCESS_DT is a DB2 date time variable with a DATE9 format. How can I declare DATE_STAMP to be a date time variable?

#!/usr/bin/ksh
DATE_STAMP=`TZ=CST+24 date +%y%m%d`
count=`db2 -x "select count(*) from schema.tablename where PROCESS_DT="$DATE_STAMP""`
echo "$count"