xuzifu666 commented on code in PR #4342: URL: https://github.com/apache/calcite/pull/4342#discussion_r2065320581
########## core/src/main/java/org/apache/calcite/sql/dialect/DuckDBSqlDialect.java: ########## @@ -0,0 +1,157 @@ +/* + * 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.calcite.sql.dialect; + +import org.apache.calcite.avatica.util.TimeUnitRange; +import org.apache.calcite.config.NullCollation; +import org.apache.calcite.rel.type.RelDataTypeSystem; +import org.apache.calcite.rel.type.RelDataTypeSystemImpl; +import org.apache.calcite.sql.SqlCall; +import org.apache.calcite.sql.SqlDialect; +import org.apache.calcite.sql.SqlLiteral; +import org.apache.calcite.sql.SqlWriter; +import org.apache.calcite.sql.fun.SqlLibraryOperators; +import org.apache.calcite.sql.parser.SqlParserPos; +import org.apache.calcite.sql.type.SqlTypeName; + +/** + * A <code>SqlDialect</code> implementation for the DuckDB database. + */ +public class DuckDBSqlDialect extends StarRocksSqlDialect { + public static final RelDataTypeSystem TYPE_SYSTEM = + new RelDataTypeSystemImpl() { + + // We can refer to document of DuckDB 1.2.x: + // https://duckdb.org/docs/stable/sql/data_types/numeric#fixed-point-decimals + @Override public int getMaxPrecision(SqlTypeName typeName) { + switch (typeName) { + case DECIMAL: + return 38; + default: + return super.getMaxPrecision(typeName); + } + } + + @Override public int getMaxScale(SqlTypeName typeName) { + switch (typeName) { + case DECIMAL: + return 38; + default: + return super.getMaxScale(typeName); + } + } + + @Override public int getMaxNumericScale() { + return getMaxScale(SqlTypeName.DECIMAL); + } + }; + + public static final SqlDialect.Context DEFAULT_CONTEXT = SqlDialect.EMPTY_CONTEXT + .withDatabaseProduct(SqlDialect.DatabaseProduct.DUCKDB) + .withIdentifierQuoteString("\"") + .withNullCollation(NullCollation.LAST) + .withDataTypeSystem(TYPE_SYSTEM); + + public static final SqlDialect DEFAULT = new DuckDBSqlDialect(DEFAULT_CONTEXT); + + /** Creates a DuckDBSqlDialect. */ + public DuckDBSqlDialect(SqlDialect.Context context) { + super(context); + } + + @Override public boolean supportsApproxCountDistinct() { + return true; + } + + @Override public void unparseCall(SqlWriter writer, SqlCall call, + int leftPrec, int rightPrec) { + switch (call.getKind()) { + case MAP_VALUE_CONSTRUCTOR: + writer.keyword(call.getOperator().getName()); + final SqlWriter.Frame mapFrame = writer.startList("{", "}"); + for (int i = 0; i < call.operandCount(); i++) { + String sep = i % 2 == 0 ? "," : ":"; + writer.sep(sep); + call.operand(i).unparse(writer, leftPrec, rightPrec); + } + writer.endList(mapFrame); + break; + case FLOOR: + if (call.operandCount() != 2) { + super.unparseCall(writer, call, leftPrec, rightPrec); + return; + } + unparseFloor(writer, call); + break; + case CHAR_LENGTH: + SqlCall lengthCall = SqlLibraryOperators.LENGTH + .createCall(SqlParserPos.ZERO, call.getOperandList()); + super.unparseCall(writer, lengthCall, leftPrec, rightPrec); + break; + default: + super.unparseCall(writer, call, leftPrec, rightPrec); + } + } + + private static void unparseFloor(SqlWriter writer, SqlCall call) { + SqlLiteral node = call.operand(1); + TimeUnitRange unit = node.getValueAs(TimeUnitRange.class); + + String format; + switch (unit) { + case YEAR: + format = "year"; + break; + case MONTH: + format = "month"; + break; + case WEEK: + format = "week"; + break; + case DAY: + format = "day"; + break; + case HOUR: + format = "hour"; + break; + case MINUTE: + format = "minute"; + break; + case SECOND: + format = "second"; + break; + case MILLISECOND: + format = "milliseconds"; + break; + case MICROSECOND: + format = "microseconds"; + break; + default: + throw new AssertionError("MYSQL does not support FLOOR for time unit: " Review Comment: It's my mistake, had fixed it, thanks. @mihaibudiu ########## core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java: ########## @@ -5958,6 +5999,13 @@ private void checkLiteral2(String expression, String expected) { .ok(expected); } + @Test void testDuckDBDecimalPrecision() { + final String sql = "SELECT CAST(1.23 AS DECIMAL(38, 37))"; + final String expected = "SELECT 1.2300000000000000000000000000000000000"; Review Comment: From definition： LAST：Nulls last for DESC and ASC. HIGH：Nulls first for DESC, nulls last for ASC. system env test： before query insert into t3 select 1,'aa'; insert into t3 select 1,'bb'; insert into t3 select 1,NULL; insert into t3 select 1,NULL; then query order by desc/asc D select * from t3 order by data asc; ┌───────┬─────────┐ │ id │ data │ │ int32 │ varchar │ ├───────┼─────────┤ │ 1 │ aa │ │ 1 │ bb │ │ 1 │ │ └───────┴─────────┘ D select * from t3 order by data desc; ┌───────┬─────────┐ │ id │ data │ │ int32 │ varchar │ ├───────┼─────────┤ │ 1 │ bb │ │ 1 │ aa │ │ 1 │ │ └───────┴─────────┘ we can find that NULL is always at last, so here should be LAST. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
