com.hazelcast.org.apache.calcite.sql.dialect.HsqldbSqlDialect Maven / Gradle / Ivy
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* 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.sql.SqlBasicCall;
import com.hazelcast.org.apache.calcite.sql.SqlCall;
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.SqlNodeList;
import com.hazelcast.org.apache.calcite.sql.SqlWriter;
import com.hazelcast.org.apache.calcite.sql.fun.SqlCase;
import com.hazelcast.org.apache.calcite.sql.fun.SqlFloorFunction;
import com.hazelcast.org.apache.calcite.sql.fun.SqlStdOperatorTable;
import com.hazelcast.org.apache.calcite.sql.parser.SqlParserPos;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
/**
* A SqlDialect
implementation for the Hsqldb database.
*/
public class HsqldbSqlDialect extends SqlDialect {
public static final SqlDialect.Context DEFAULT_CONTEXT = SqlDialect.EMPTY_CONTEXT
.withDatabaseProduct(SqlDialect.DatabaseProduct.HSQLDB);
public static final SqlDialect DEFAULT = new HsqldbSqlDialect(DEFAULT_CONTEXT);
/** Creates an HsqldbSqlDialect. */
public HsqldbSqlDialect(Context context) {
super(context);
}
@Override public boolean supportsCharSet() {
return false;
}
@Override public boolean supportsAggregateFunctionFilter() {
return false;
}
@Override public boolean supportsWindowFunctions() {
return false;
}
@Override public void unparseCall(SqlWriter writer, SqlCall call,
int leftPrec, int rightPrec) {
switch (call.getKind()) {
case FLOOR:
if (call.operandCount() != 2) {
super.unparseCall(writer, call, leftPrec, rightPrec);
return;
}
final SqlLiteral timeUnitNode = call.operand(1);
final TimeUnitRange timeUnit = timeUnitNode.getValueAs(TimeUnitRange.class);
final String translatedLit = convertTimeUnit(timeUnit);
SqlCall call2 = SqlFloorFunction.replaceTimeUnitOperand(call, translatedLit,
timeUnitNode.getParserPosition());
SqlFloorFunction.unparseDatetimeFunction(writer, call2, "TRUNC", true);
break;
default:
super.unparseCall(writer, call, leftPrec, rightPrec);
}
}
@Override public void unparseOffsetFetch(SqlWriter writer, @Nullable SqlNode offset,
@Nullable SqlNode fetch) {
unparseFetchUsingLimit(writer, offset, fetch);
}
@Override public SqlNode rewriteSingleValueExpr(SqlNode aggCall) {
final SqlNode operand = ((SqlBasicCall) aggCall).operand(0);
final SqlLiteral nullLiteral = SqlLiteral.createNull(SqlParserPos.ZERO);
final SqlNode unionOperand = SqlStdOperatorTable.VALUES.createCall(SqlParserPos.ZERO,
SqlLiteral.createApproxNumeric("0", SqlParserPos.ZERO));
// For hsqldb, generate
// CASE COUNT(*)
// WHEN 0 THEN NULL
// WHEN 1 THEN MIN()
// ELSE (VALUES 1 UNION ALL VALUES 1)
// END
final SqlNode caseExpr =
new SqlCase(SqlParserPos.ZERO,
SqlStdOperatorTable.COUNT.createCall(SqlParserPos.ZERO, operand),
SqlNodeList.of(
SqlLiteral.createExactNumeric("0", SqlParserPos.ZERO),
SqlLiteral.createExactNumeric("1", SqlParserPos.ZERO)),
SqlNodeList.of(
nullLiteral,
SqlStdOperatorTable.MIN.createCall(SqlParserPos.ZERO, operand)),
SqlStdOperatorTable.SCALAR_QUERY.createCall(SqlParserPos.ZERO,
SqlStdOperatorTable.UNION_ALL
.createCall(SqlParserPos.ZERO, unionOperand, unionOperand)));
LOGGER.debug("SINGLE_VALUE rewritten into [{}]", caseExpr);
return caseExpr;
}
private static String convertTimeUnit(TimeUnitRange unit) {
switch (unit) {
case YEAR:
return "YYYY";
case MONTH:
return "MM";
case DAY:
return "DD";
case WEEK:
return "WW";
case HOUR:
return "HH24";
case MINUTE:
return "MI";
case SECOND:
return "SS";
default:
throw new AssertionError("could not convert time unit to HSQLDB equivalent: "
+ unit);
}
}
}
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