Hi Roberto

> This is a valid sentence with SQL Server:

Really? what a pitty for MSSQL users.

> UPDATE MAT SET MAT.MT=137
> FROM MAT INNER JOIN ALU ON MAT.ALREG = ALU.ALREG
> WHERE ALU.EDCOD='TWQ';
> With FireBird 1.5 I get Token unknow line 2 char 1 FROM
> How can I do this kind of UPDATE with FireBird 1.5?
> How can I do a similar DELETE (with JOIN) with FireBird 1.5?
>

You are allready saying "UPDATE MAT",
so, what is it for "FROM MAT" ?

Try this:
UPDATE MAT SET MAT.MT=137
WHERE EXISTS (SELECT 1 FROM ALU WHERE MAT.ALREG = ALU.ALREG
AND ALU.EDCOD='TWQ')

Regards.
Ali