Question

I can’t use the jOOQ generator to generate a Dual.java class for MySQL,
but inverse in PostgreSQL

I have included “dual” in the code generation config file:

<includes>dual</includes>

<name>org.jooq.util.DefaultGenerator</name>

I’m using jOOQ’s latest version: 2.4.0. What could be the problem?

Answer 1

With jOOQ, you don’t have to worry about the DUAL table. jOOQ handles that for you. The following jOOQ query:

create.select(val(1), val(2)).fetch();

Will render

-- MySQL
SELECT 1, 2 FROM DUAL

-- Postgres
SELECT 1, 2

For more info about the DUAL tables and similar constructs in various SQL dialects, read this blog post:

http://blog.jooq.org/2011/10/16/sql-trouble-with-dummy-tables/