SQL script to fit decimal point of a column - PostgreSQL

I have a table in PostgreSQL that has the field IdProduto and Quantidade . The Quantidade column values were written to the wrong decimal places.

Ex: 9000,000 was written when it should be 9,000 . The lack of a comma caused the value to rise from 9 units to 9 thousand units.

Is there a way I can do this via SQL script for all products?