Casting Strint to integer in liferay dynamic query - liferay

Question

I have been using dynamic query for a project.
Here is an scenario for which I am facing problem.
For a table xyz the column version is stored as varchar (I know it's a poor design, but it's too late to change now) and has values as 9,12.
For the query :
select max(version)
from xyz
where something = 'abc';
I am getting the output as 9 instead of 12.
The dynamic query for the same is:
ClassLoader classLoader = PortletBeanLocatorUtil.getBeanLocator(ClpSerializer.getServletContextName()).getClassLoader();
DynamicQuery dynamicQuery = DynamicQueryFactoryUtil.forClass(xyz.class, classLoader);
dynamicQuery.setProjection(ProjectionFactoryUtil.max("version"));
dynamicQuery.add(PropertyFactoryUtil.forName("something").eq("abc"));
List<Object> list = xyzLocalServiceUtil.dynamicQuery(dynamicQuery);
The query which is giving the correct value is :
select max(cast(version as signed))
from xyz
where something = 'abc';
Now, I want it to be in the dynamic query, how can I do that?
I am using liferay-6.2-ce

Answer 1

Try using ProjectionFactoryUtil.sqlProjection method.
That method allows using functions that are executed by SQL engine.
For example, I am using following code in order to get the max length of a string column called 'content':
Projection maxSizeProjection = ProjectionFactoryUtil.sqlProjection(
"max(length(content)) as maxSize", new String[] {"maxSize"},
new Type[] {Type.BIG_DECIMAL});
The same thing can be done with dynamic query criterions using RestrictionsFactoryUtil.sqlRestriction in case you want to use a SQL function in a condition.
In your case try following code:
import com.liferay.portal.kernel.dao.orm.ProjectionFactoryUtil;
import com.liferay.portal.kernel.dao.orm.Type;
...
Projection maxSizeProjection = ProjectionFactoryUtil.sqlProjection(
"max(cast(version as signed)) as maxVersion",
new String[] {"maxVersion"}, new Type[] {Type.BIG_DECIMAL});
dynamicQuery.setProjection(maxSizeProjection);