Hi Priyan,

Have u noticed one thing.Try this

CREATE TABLE testing(id INTEGER,name VARCHAR(10));
INSERT INTO testing VALUES (1,'1000,1010');
SELECT * FROM table_name WHERE table_id IN (SELECT name FROM testing);

The above query returns only one record from the table as per the first value from the field.

This is because the difference as follows

SELECT * FROM table_name WHERE table_id IN ('1000,1010'), trims the string to the INTEGER and takes just the first value.so the query will work as
SELECT * FROM table_name WHERE table_id IN ('1000');

Might be the same thing happens in the GROUP_CONCAT().

As you said that it will be very tedious for handling strings, each values has to be concated as a string and to get the result from the query.

Hope believe there will be more flexible String Functions are expected in MYSQL5.1.

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-Murali..