support functions/expression in condition

[mmm8955405]

SELECT name, SUM ( id>1)
FROM foo
WHERE ..

public class Sum<T> extends AbstractUniTypeFunction<T, Sum<T>> {

    private final VisitableCondition<T> condition;

    private Sum(BindableColumn<T> column, VisitableCondition<T> condition) {
        super(column);
        this.condition = condition;
    }

    @Override
    public String renderWithTableAlias(TableAliasCalculator tableAliasCalculator) {
    	ColumnAndConditionCriterion<T>  criteion = ColumnAndConditionCriterion
    			.withColumn(column)
    			.withCondition(condition).build();
        String s = criteion.toString();
    	
        return "sum(" //$NON-NLS-1$
                + column.renderWithTableAlias(tableAliasCalculator)
                + s
                + ")"; //$NON-NLS-1$
    }

    @Override
    protected Sum<T> copy() {
        return new Sum<>(column, condition);
    }

    public static <T> Sum<T> of(BindableColumn<T> column, VisitableCondition<T> condition) {
        return new Sum<>(column, condition);
    }
}

How to render VisitableCondition ？

I see that this method is outdated

CriterionRenderer.withCriterion(subCriterion).withSequence(sequence)
  .withRenderingStrategy(renderingStrategy)
  .withTableAliasCalculator(tableAliasCalculator)
  .build()
  .render();

[jeffgbutler]

criterion.toString() won't work - you will need to use the CriterionRenderer. But you won't have access to the required parameters for the builder. I'll need to make a change to support rendering for cases like this. Shouldn't be too difficult.

[mmm8955405]

If that's the case, it's really great

[jeffgbutler]

I've updated the rendering to support this. I also went ahead and implemented the change to the existing sum function to support the original request. You can see how it is implemented here: https://github.com/mybatis/mybatis-dynamic-sql/blob/master/src/main/java/org/mybatis/dynamic/sql/select/aggregate/Sum.java

Thanks for the idea - it caused a good refactoring in the library.