Thomas Fox created TORQUE-290:
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Summary: Improve building from clause in subselect
Key: TORQUE-290
URL: https://issues.apache.org/jira/browse/TORQUE-290
Project: Torque
Issue Type: Improvement
Components: Runtime
Affects Versions: 4.0
Reporter: Thomas Fox
Assignee: Thomas Fox
Currently, it is not easily possible to reference columns in the main select
from a subselect.
For example:
Select authors which have published more than three books
SELECT * FROM author WHERE (SELECT COUNT(*) FROM book WHERE
book.author_id=author.author_id)=1
One would like to achieve this by
Criteria subselect = new Criteria();
subselect.where(BookPeer.AUTHOR_ID, AuthorPeer.AUTHOR_ID);
subselect.addSelectColumn(new Count("*"));
Criteria criteria = new Criteria();
criteria.where(subselect, 1);
List<Author> result = AuthorPeer.doSelect(criteria);
but the SQL results in (note the additional author in the from clause of the
subselect)
SELECT * FROM author WHERE (SELECT COUNT(*) FROM book, author WHERE
book.author_id=author.author_id)=1
So the desired behavior is:
If a table also exists in the from clause of the outer criteria, it should not
be added to the from clause of the subselect
NOTE1: This change can change the behaviour of Torque in existing code
NOTE2: Workarounds exist, e.g. defining the FROM clause of the subselect
manually using Criteria.addFrom() or using "new
ColumnImpl(null,null,null,AuthorPeer.AUTHOR_ID.getSqlExpression())" as join
column in the WHERE clause of the subselect.Currently, it is not easily
possible to reference columns in the main select from a subselect.
For examle
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