SQL & PL/SQL :: Oracle 10g Database - Building Dynamic Insert Statement?

i'm working in an Oracle 10g database on an IBM AIX server.

I have 3 tables (tables A, B and C).

Table A has columns -- product, rate and expiration date.

Table B has columns -- product, rate and deductible.

Table C has columns -- product, rider, gender, age and rate.

I also have a Master table which is used to store the data from Tables A, B and C via the insert statement.

I'm trying to create a dynamic SQL insert statement using a shell script to insert data from the columns in Tables A, B and C into my Master table. Master table does contains all columns from Tables A, B and C, although a column name could be spelled differently. For example, Master table contains a column named "deduct", while Table B has the same column spelled as "deductible".

I build the dynamic query using a for loop in my shell script (see below).

The problem is that i can't get the correct columns in the Master table in the dynamic SQL for the insert because depending on the table i'm selection from, the columns are different. So how do i get the correct columns in the SQL for the Master table?

Example Shell Script

--Archive_Rates.txt contains: Table A, Table B, Table C (but the next time my process runs, Archive_Rates might contain Table D, Table E and Table F -- each which have different column...but all columns are still in the Master table)

for tbl in `more Archive_Rates.txt`
do
echo 'BEGIN WORK; ' > rc1.sql
echo ' ' >> rc1.sql
echo 'insert into Master' >> rc1.sql
echo '(prod, rate, rate_exp) ' >> rc1.sql

[code].....