com.hazelcast.org.apache.calcite.sql.fun.SqlCountAggFunction Maven / Gradle / Ivy
/*
* 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 com.hazelcast.org.apache.calcite.sql.fun;
import com.hazelcast.org.apache.calcite.config.CalciteSystemProperty;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.apache.calcite.rel.type.RelDataTypeFactory;
import com.hazelcast.org.apache.calcite.sql.SqlAggFunction;
import com.hazelcast.org.apache.calcite.sql.SqlCall;
import com.hazelcast.org.apache.calcite.sql.SqlFunctionCategory;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import com.hazelcast.org.apache.calcite.sql.SqlSplittableAggFunction;
import com.hazelcast.org.apache.calcite.sql.SqlSyntax;
import com.hazelcast.org.apache.calcite.sql.type.OperandTypes;
import com.hazelcast.org.apache.calcite.sql.type.ReturnTypes;
import com.hazelcast.org.apache.calcite.sql.type.SqlOperandTypeChecker;
import com.hazelcast.org.apache.calcite.sql.type.SqlTypeName;
import com.hazelcast.org.apache.calcite.sql.validate.SqlValidator;
import com.hazelcast.org.apache.calcite.sql.validate.SqlValidatorScope;
import com.hazelcast.org.apache.calcite.util.Optionality;
import com.hazelcast.com.google.common.collect.ImmutableList;
import java.util.List;
/**
* Definition of the SQL COUNT
aggregation function.
*
* COUNT
is an aggregator which returns the number of rows which
* have gone into it. With one argument (or more), it returns the number of rows
* for which that argument (or all) is not null
.
*/
public class SqlCountAggFunction extends SqlAggFunction {
//~ Constructors -----------------------------------------------------------
public SqlCountAggFunction(String name) {
this(name, CalciteSystemProperty.STRICT.value() ? OperandTypes.ANY : OperandTypes.ONE_OR_MORE);
}
public SqlCountAggFunction(String name,
SqlOperandTypeChecker sqlOperandTypeChecker) {
super(name, null, SqlKind.COUNT, ReturnTypes.BIGINT, null,
sqlOperandTypeChecker, SqlFunctionCategory.NUMERIC, false, false,
Optionality.FORBIDDEN);
}
//~ Methods ----------------------------------------------------------------
@Override public SqlSyntax getSyntax() {
return SqlSyntax.FUNCTION_STAR;
}
@SuppressWarnings("deprecation")
public List getParameterTypes(RelDataTypeFactory typeFactory) {
return ImmutableList.of(
typeFactory.createTypeWithNullability(
typeFactory.createSqlType(SqlTypeName.ANY), true));
}
@SuppressWarnings("deprecation")
public RelDataType getReturnType(RelDataTypeFactory typeFactory) {
return typeFactory.createSqlType(SqlTypeName.BIGINT);
}
public RelDataType deriveType(
SqlValidator validator,
SqlValidatorScope scope,
SqlCall call) {
// Check for COUNT(*) function. If it is we don't
// want to try and derive the "*"
if (call.isCountStar()) {
return validator.getTypeFactory().createSqlType(
SqlTypeName.BIGINT);
}
return super.deriveType(validator, scope, call);
}
@Override public T unwrap(Class clazz) {
if (clazz == SqlSplittableAggFunction.class) {
return clazz.cast(SqlSplittableAggFunction.CountSplitter.INSTANCE);
}
return super.unwrap(clazz);
}
}