com.hazelcast.org.apache.calcite.sql.dialect.ClickHouseSqlDialect Maven / Gradle / Ivy
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* 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.
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package com.hazelcast.org.apache.calcite.sql.dialect;
import com.hazelcast.org.apache.calcite.avatica.util.TimeUnitRange;
import com.hazelcast.org.apache.calcite.config.NullCollation;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.apache.calcite.sql.SqlAbstractDateTimeLiteral;
import com.hazelcast.org.apache.calcite.sql.SqlBasicTypeNameSpec;
import com.hazelcast.org.apache.calcite.sql.SqlCall;
import com.hazelcast.org.apache.calcite.sql.SqlDataTypeSpec;
import com.hazelcast.org.apache.calcite.sql.SqlDateLiteral;
import com.hazelcast.org.apache.calcite.sql.SqlDialect;
import com.hazelcast.org.apache.calcite.sql.SqlLiteral;
import com.hazelcast.org.apache.calcite.sql.SqlNode;
import com.hazelcast.org.apache.calcite.sql.SqlTimeLiteral;
import com.hazelcast.org.apache.calcite.sql.SqlTimestampLiteral;
import com.hazelcast.org.apache.calcite.sql.SqlWriter;
import com.hazelcast.org.apache.calcite.sql.fun.SqlStdOperatorTable;
import com.hazelcast.org.apache.calcite.sql.parser.SqlParserPos;
import com.hazelcast.org.apache.calcite.sql.type.BasicSqlType;
import com.hazelcast.org.apache.calcite.sql.type.SqlTypeName;
import com.hazelcast.org.apache.calcite.util.RelToSqlConverterUtil;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
import static java.util.Objects.requireNonNull;
/**
* A SqlDialect
implementation for the ClickHouse database.
*/
public class ClickHouseSqlDialect extends SqlDialect {
public static final SqlDialect.Context DEFAULT_CONTEXT = SqlDialect.EMPTY_CONTEXT
.withDatabaseProduct(SqlDialect.DatabaseProduct.CLICKHOUSE)
.withIdentifierQuoteString("`")
.withNullCollation(NullCollation.LOW);
public static final SqlDialect DEFAULT = new ClickHouseSqlDialect(DEFAULT_CONTEXT);
/** Creates a ClickHouseSqlDialect. */
public ClickHouseSqlDialect(Context context) {
super(context);
}
@Override public boolean supportsCharSet() {
return false;
}
@Override public boolean supportsNestedAggregations() {
return false;
}
@Override public boolean supportsWindowFunctions() {
return false;
}
@Override public boolean supportsAliasedValues() {
return false;
}
@Override public CalendarPolicy getCalendarPolicy() {
return CalendarPolicy.SHIFT;
}
@Override public @Nullable SqlNode getCastSpec(RelDataType type) {
if (type instanceof BasicSqlType) {
SqlTypeName typeName = type.getSqlTypeName();
switch (typeName) {
case VARCHAR:
return createSqlDataTypeSpecByName("String", typeName);
case TINYINT:
return createSqlDataTypeSpecByName("Int8", typeName);
case SMALLINT:
return createSqlDataTypeSpecByName("Int16", typeName);
case INTEGER:
return createSqlDataTypeSpecByName("Int32", typeName);
case BIGINT:
return createSqlDataTypeSpecByName("Int64", typeName);
case FLOAT:
return createSqlDataTypeSpecByName("Float32", typeName);
case DOUBLE:
return createSqlDataTypeSpecByName("Float64", typeName);
case DATE:
return createSqlDataTypeSpecByName("Date", typeName);
case TIMESTAMP:
case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
return createSqlDataTypeSpecByName("DateTime", typeName);
default:
break;
}
}
return super.getCastSpec(type);
}
private static SqlDataTypeSpec createSqlDataTypeSpecByName(String typeAlias,
SqlTypeName typeName) {
SqlBasicTypeNameSpec spec = new SqlBasicTypeNameSpec(typeName, SqlParserPos.ZERO) {
@Override public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
// unparse as an identifier to ensure that type names are cased correctly
writer.identifier(typeAlias, true);
}
};
return new SqlDataTypeSpec(spec, SqlParserPos.ZERO);
}
@Override public void unparseDateTimeLiteral(SqlWriter writer,
SqlAbstractDateTimeLiteral literal, int leftPrec, int rightPrec) {
String toFunc;
if (literal instanceof SqlDateLiteral) {
toFunc = "toDate";
} else if (literal instanceof SqlTimestampLiteral) {
toFunc = "toDateTime";
} else if (literal instanceof SqlTimeLiteral) {
toFunc = "toTime";
} else {
throw new RuntimeException("ClickHouse does not support DateTime literal: "
+ literal);
}
writer.literal(toFunc + "('" + literal.toFormattedString() + "')");
}
@Override public void unparseOffsetFetch(SqlWriter writer, @Nullable SqlNode offset,
@Nullable SqlNode fetch) {
requireNonNull(fetch, "fetch");
writer.newlineAndIndent();
final SqlWriter.Frame frame =
writer.startList(SqlWriter.FrameTypeEnum.FETCH);
writer.keyword("LIMIT");
if (offset != null) {
offset.unparse(writer, -1, -1);
writer.sep(",", true);
}
fetch.unparse(writer, -1, -1);
writer.endList(frame);
}
@Override public void unparseCall(SqlWriter writer, SqlCall call,
int leftPrec, int rightPrec) {
if (call.getOperator() == SqlStdOperatorTable.SUBSTRING) {
RelToSqlConverterUtil.specialOperatorByName("substring")
.unparse(writer, call, 0, 0);
} else {
switch (call.getKind()) {
case FLOOR:
if (call.operandCount() != 2) {
super.unparseCall(writer, call, leftPrec, rightPrec);
return;
}
unparseFloor(writer, call);
break;
case COUNT:
// CH returns NULL rather than 0 for COUNT(DISTINCT) of NULL values.
// https://github.com/yandex/ClickHouse/issues/2494
// Wrap the call in a CH specific coalesce (assumeNotNull).
if (call.getFunctionQuantifier() != null
&& call.getFunctionQuantifier().toString().equals("DISTINCT")) {
writer.print("assumeNotNull");
SqlWriter.Frame frame = writer.startList("(", ")");
super.unparseCall(writer, call, leftPrec, rightPrec);
writer.endList(frame);
} else {
super.unparseCall(writer, call, leftPrec, rightPrec);
}
break;
default:
super.unparseCall(writer, call, leftPrec, rightPrec);
}
}
}
/**
* Unparses datetime floor for ClickHouse.
*
* @param writer Writer
* @param call Call
*/
private static void unparseFloor(SqlWriter writer, SqlCall call) {
final SqlLiteral timeUnitNode = call.operand(1);
TimeUnitRange unit = timeUnitNode.getValueAs(TimeUnitRange.class);
String funName;
switch (unit) {
case YEAR:
funName = "toStartOfYear";
break;
case MONTH:
funName = "toStartOfMonth";
break;
case WEEK:
funName = "toMonday";
break;
case DAY:
funName = "toDate";
break;
case HOUR:
funName = "toStartOfHour";
break;
case MINUTE:
funName = "toStartOfMinute";
break;
default:
throw new RuntimeException("ClickHouse does not support FLOOR for time unit: "
+ unit);
}
writer.print(funName);
SqlWriter.Frame frame = writer.startList("(", ")");
call.operand(0).unparse(writer, 0, 0);
writer.endList(frame);
}
}
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