| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.phoenix.compile; |
| |
| import java.sql.SQLException; |
| import java.util.LinkedHashSet; |
| import java.util.List; |
| import java.util.Set; |
| |
| import org.apache.phoenix.compile.GroupByCompiler.GroupBy; |
| import org.apache.phoenix.exception.SQLExceptionCode; |
| import org.apache.phoenix.exception.SQLExceptionInfo; |
| import org.apache.phoenix.expression.Expression; |
| import org.apache.phoenix.expression.LiteralExpression; |
| import org.apache.phoenix.parse.AndParseNode; |
| import org.apache.phoenix.parse.BooleanParseNodeVisitor; |
| import org.apache.phoenix.parse.ColumnParseNode; |
| import org.apache.phoenix.parse.FunctionParseNode; |
| import org.apache.phoenix.parse.ParseNode; |
| import org.apache.phoenix.parse.SelectStatement; |
| import org.apache.phoenix.parse.SelectStatementRewriter; |
| import org.apache.phoenix.schema.ColumnRef; |
| import org.apache.phoenix.schema.TypeMismatchException; |
| import org.apache.phoenix.schema.types.PBoolean; |
| |
| |
| public class HavingCompiler { |
| |
| private HavingCompiler() { |
| } |
| |
| public static Expression compile(StatementContext context, SelectStatement statement, GroupBy groupBy) throws SQLException { |
| ParseNode having = statement.getHaving(); |
| if (having == null) { |
| return null; |
| } |
| ExpressionCompiler expressionBuilder = new ExpressionCompiler(context, groupBy); |
| Expression expression = having.accept(expressionBuilder); |
| if (expression.getDataType() != PBoolean.INSTANCE) { |
| throw TypeMismatchException.newException(PBoolean.INSTANCE, expression.getDataType(), expression.toString()); |
| } |
| if (LiteralExpression.isBooleanFalseOrNull(expression)) { |
| context.setScanRanges(ScanRanges.NOTHING); |
| return null; |
| } else if (LiteralExpression.isTrue(expression)) { |
| return null; |
| } |
| if (!expressionBuilder.isAggregate()) { |
| throw new SQLExceptionInfo.Builder(SQLExceptionCode.ONLY_AGGREGATE_IN_HAVING_CLAUSE).build().buildException(); |
| } |
| return expression; |
| } |
| |
| public static SelectStatement rewrite(StatementContext context, SelectStatement statement, GroupBy groupBy) throws SQLException { |
| ParseNode having = statement.getHaving(); |
| if (having == null) { |
| return statement; |
| } |
| HavingClauseVisitor visitor = new HavingClauseVisitor(context, groupBy); |
| having.accept(visitor); |
| statement = SelectStatementRewriter.moveFromHavingToWhereClause(statement, visitor.getMoveToWhereClauseExpressions()); |
| return statement; |
| } |
| |
| /** |
| * |
| * Visitor that figures out if an expression can be moved from the HAVING clause to |
| * the WHERE clause, since it's more optimal to pre-filter instead of post-filter. |
| * |
| * The visitor traverses through AND expressions only and into comparison expresssions. |
| * If a comparison expression uses a GROUP BY column and does not use any aggregate |
| * functions, then it's moved. For example, these HAVING expressions would be moved: |
| * |
| * select count(1) from atable group by a_string having a_string = 'foo' |
| * select count(1) from atable group by a_date having round(a_date,'hour') > ? |
| * select count(1) from atable group by a_date,a_string having a_date > ? or a_string = 'a' |
| * select count(1) from atable group by a_string,b_string having a_string = 'a' and b_string = 'b' |
| * |
| * while these would not be moved: |
| * |
| * select count(1) from atable having min(a_integer) < 5 |
| * select count(1) from atable group by a_string having count(a_string) >= 1 |
| * select count(1) from atable group by a_date,a_string having a_date > ? or min(a_string) = 'a' |
| * select count(1) from atable group by a_date having round(min(a_date),'hour') < ? |
| * |
| * |
| * @since 0.1 |
| */ |
| private static class HavingClauseVisitor extends BooleanParseNodeVisitor<Void> { |
| private ParseNode topNode = null; |
| private boolean hasNoAggregateFunctions = true; |
| private Boolean hasOnlyAggregateColumns; |
| private final StatementContext context; |
| private final GroupBy groupBy; |
| private final Set<ParseNode> moveToWhereClause = new LinkedHashSet<ParseNode>(); |
| |
| HavingClauseVisitor(StatementContext context, GroupBy groupBy) { |
| this.context = context; |
| this.groupBy = groupBy; |
| } |
| |
| public Set<ParseNode> getMoveToWhereClauseExpressions() { |
| return moveToWhereClause; |
| } |
| |
| @Override |
| protected boolean enterBooleanNode(ParseNode node) throws SQLException { |
| if (topNode == null) { |
| topNode = node; |
| } |
| |
| return true; |
| } |
| |
| @Override |
| protected Void leaveBooleanNode(ParseNode node, List<Void> l) throws SQLException { |
| if (topNode == node) { |
| if ( hasNoAggregateFunctions && !Boolean.FALSE.equals(hasOnlyAggregateColumns)) { |
| moveToWhereClause.add(node); |
| } |
| hasNoAggregateFunctions = true; |
| hasOnlyAggregateColumns = null; |
| topNode = null; |
| } |
| |
| return null; |
| } |
| |
| @Override |
| protected boolean enterNonBooleanNode(ParseNode node) throws SQLException { |
| return true; |
| } |
| |
| @Override |
| protected Void leaveNonBooleanNode(ParseNode node, List<Void> l) throws SQLException { |
| return null; |
| } |
| |
| @Override |
| public boolean visitEnter(AndParseNode node) throws SQLException { |
| return true; |
| } |
| |
| @Override |
| public Void visitLeave(AndParseNode node, List<Void> l) throws SQLException { |
| return null; |
| } |
| |
| @Override |
| public boolean visitEnter(FunctionParseNode node) throws SQLException { |
| boolean isAggregate = node.isAggregate(); |
| this.hasNoAggregateFunctions = this.hasNoAggregateFunctions && !isAggregate; |
| return !isAggregate && super.visitEnter(node); |
| } |
| |
| @Override |
| public Void visit(ColumnParseNode node) throws SQLException { |
| ColumnRef ref = context.getResolver().resolveColumn(node.getSchemaName(), node.getTableName(), node.getName()); |
| boolean isAggregateColumn = groupBy.getExpressions().indexOf(ref.newColumnExpression(node.isTableNameCaseSensitive(), node.isCaseSensitive())) >= 0; |
| if (hasOnlyAggregateColumns == null) { |
| hasOnlyAggregateColumns = isAggregateColumn; |
| } else { |
| hasOnlyAggregateColumns &= isAggregateColumn; |
| } |
| |
| return null; |
| } |
| |
| } |
| } |