Strange in problem in table linking

Hi Everybody,

I'd designed a report using 3 tables. Namely A,B,C

Linking these tables using inner joins.

For Tables B,C, the parameter fields restricts the result (Using selecton formula)

For the matching records in table A, I'm using a single columns. (No direct conditions for table A)

While trying to run my report first time, it takes the table order A,B,C and trying to pull all the records from table A and try to match with other tables. (which is completly insane) So it was running infinitely.

Still the first instance running, Running the same report with same parameter values, now it takes the tables in the order B,C,A so that I got the result in seconds.

I'm using mySQL database. I just used "EXPLAIN" command to know the table orders during the processing.

How can I force the optimizer to take a specific order of tables?

Thanks in advance