gistfile1.sql

CREATE TABLE `foo` (
    `id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY,
    `name` varchar(255) NOT NULL
);

CREATE TABLE `bar` (
    `id` integer AUTO_INCREMENT NOT NULL PRIMARY KEY,
    `name` varchar(255) NOT NULL,
    `foo_id` integer NOT NULL
);

INSERT INTO foo(id, name) values (1, 'Foo 1');
INSERT INTO foo(id, name) values (2, 'Foo 2');
INSERT INTO foo(id, name) values (3, 'Foo 3');
INSERT INTO bar(id, name, foo_id) values(1, 'Bar 1', 1);
INSERT INTO bar(id, name, foo_id) values(3, 'Bar 3', 3);

SELECT foo.id, foo.name, (bar.id is not null) as bar_exists
FROM foo LEFT OUTER JOIN bar ON foo.id = bar.foo_id
WHERE bar.id is null OR bar.name = 'Bar 3';

SELECT foo.id, foo.name, (bar.id is not null) as bar_exists
FROM foo LEFT OUTER JOIN bar ON foo.id = bar.foo_id AND bar.name = 'Bar 3';