Can I mysqldump an entire database while using where='condition' on individual tables?
You will have to custom script each table 

The --where option is designed to help mysqldump a single table

Here is a post I made back in August 15, 2011

Is it possible to mysqldump a subset of a database required to reproduce a query?

Here is an crazy example

Suppose the table is this in the myworld database:

CREATE TABLE data_for_world
(
    id int not auto_increment,
    continent varchar(16),
    primary key (id)
);
insert into data_world (continent)
values ('Asia'),('Africa'),('Eupore'),
('NorthAmerica'),('SouthAmerica'),
('Australia'),('Antarctica');


and you want to break it up into two dumps


one with continents that start with A
one with continents that do not start with A


You will need three files (one for the database schema, and two for the data)

mysqldump --no-data --database myworld &gt; myworld_schema.sql
mysqldump --no-create-info myworld data_for_world --where="substr(continent,1,1)='A'" &gt; data1.sql
mysqldump --no-create-info myworld data_for_world --where="substr(continent,1,1)&lt;&gt;'A'" &gt; data2.sql