MultiDistinctFunctionStrategy.java

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package org.apache.doris.nereids.rules.rewrite;

import org.apache.doris.nereids.trees.expressions.NamedExpression;
import org.apache.doris.nereids.trees.expressions.functions.agg.AggregateFunction;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.logical.LogicalAggregate;
import org.apache.doris.nereids.util.AggregateUtils;
import org.apache.doris.nereids.util.ExpressionUtils;

import java.util.List;

/**
 * Processes all distinct function use multi distinct function
 */
public class MultiDistinctFunctionStrategy {
    /** rewrite aggFunc(distinct) to multi_distinct_xxx */
    public static LogicalAggregate<? extends Plan> rewrite(LogicalAggregate<? extends Plan> aggregate) {
        List<NamedExpression> newOutput = ExpressionUtils.rewriteDownShortCircuit(
                aggregate.getOutputExpressions(), outputChild -> {
                    if (outputChild instanceof AggregateFunction) {
                        return AggregateUtils.tryConvertToMultiDistinct((AggregateFunction) outputChild);
                    }
                    return outputChild;
                });
        return aggregate.withAggOutput(newOutput);
    }
}