[CALCITE-6257] StarRocks dialect implementation

core/src/main/java/org/apache/calcite/sql/SqlDialect.java

@@ -1393,6 +1393,7 @@ public enum DatabaseProduct {
     VERTICA("Vertica", "\"", NullCollation.HIGH),
     SQLSTREAM("SQLstream", "\"", NullCollation.HIGH),
     SPARK("Spark", null, NullCollation.LOW),
+    STARROCKS("StarRocks", "`", NullCollation.LOW),
 
     /** Paraccel, now called Actian Matrix. Redshift is based on this, so
      * presumably the dialect capabilities are similar. */

core/src/main/java/org/apache/calcite/sql/SqlDialectFactoryImpl.java

@@ -47,6 +47,7 @@
 import org.apache.calcite.sql.dialect.RedshiftSqlDialect;
 import org.apache.calcite.sql.dialect.SnowflakeSqlDialect;
 import org.apache.calcite.sql.dialect.SparkSqlDialect;
+import org.apache.calcite.sql.dialect.StarRocksSqlDialect;
 import org.apache.calcite.sql.dialect.SybaseSqlDialect;
 import org.apache.calcite.sql.dialect.TeradataSqlDialect;
 import org.apache.calcite.sql.dialect.VerticaSqlDialect;
@@ -230,6 +231,8 @@ public class SqlDialectFactoryImpl implements SqlDialectFactory {
       return SnowflakeSqlDialect.DEFAULT;
     case SPARK:
       return SparkSqlDialect.DEFAULT;
+    case STARROCKS:
+      return StarRocksSqlDialect.DEFAULT;
     case SYBASE:
       return SybaseSqlDialect.DEFAULT;
     case TERADATA:

core/src/main/java/org/apache/calcite/sql/dialect/StarRocksSqlDialect.java

@@ -0,0 +1,133 @@
+/*
+ * 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.RelDataType;
+import org.apache.calcite.sql.SqlAbstractDateTimeLiteral;
+import org.apache.calcite.sql.SqlAlienSystemTypeNameSpec;
+import org.apache.calcite.sql.SqlCall;
+import org.apache.calcite.sql.SqlDataTypeSpec;
+import org.apache.calcite.sql.SqlDialect;
+import org.apache.calcite.sql.SqlLiteral;
+import org.apache.calcite.sql.SqlNode;
+import org.apache.calcite.sql.SqlWriter;
+import org.apache.calcite.sql.fun.SqlFloorFunction;
+import org.apache.calcite.sql.parser.SqlParserPos;
+import org.apache.calcite.sql.type.SqlTypeName;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import static org.apache.calcite.util.RelToSqlConverterUtil.unparseHiveTrim;
+
+/**
+ * A <code>SqlDialect</code> implementation for the StarRocks database.
+ */
+public class StarRocksSqlDialect extends MysqlSqlDialect {
+
+  public static final SqlDialect.Context DEFAULT_CONTEXT = SqlDialect.EMPTY_CONTEXT
+      .withDatabaseProduct(SqlDialect.DatabaseProduct.STARROCKS)
+      .withIdentifierQuoteString("`")
+      .withNullCollation(NullCollation.LOW);
+
+  public static final SqlDialect DEFAULT = new StarRocksSqlDialect(DEFAULT_CONTEXT);
+
+  /**
+   * Creates a StarRocksSqlDialect.
+   */
+  public StarRocksSqlDialect(Context context) {
+    super(context);
+  }
+
+  @Override public boolean supportsGroupByWithRollup() {
+    return false;
+  }
+
+  @Override public boolean supportsTimestampPrecision() {
+    return false;
+  }
+
+  @Override public boolean supportsApproxCountDistinct() {
+    return true;
+  }
+
+  @Override public void unparseCall(SqlWriter writer, SqlCall call, int leftPrec, int rightPrec) {
+    switch (call.getKind()) {
+    case ARRAY_VALUE_CONSTRUCTOR:
+      final SqlWriter.Frame arrayFrame = writer.startList("[", "]");
+      for (SqlNode operand : call.getOperandList()) {
+        writer.sep(",");
+        operand.unparse(writer, leftPrec, rightPrec);
+      }
+      writer.endList(arrayFrame);
+      break;
+    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 TRIM:
+      unparseHiveTrim(writer, call, leftPrec, rightPrec);
+      break;
+    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);
+      SqlCall newCall =
+          SqlFloorFunction.replaceTimeUnitOperand(call, timeUnit.name(),
+              timeUnitNode.getParserPosition());
+      SqlFloorFunction.unparseDatetimeFunction(writer, newCall, "DATE_TRUNC", false);
+      break;
+    default:
+      super.unparseCall(writer, call, leftPrec, rightPrec);
+      break;
+    }
+  }
+
+  @Override public @Nullable SqlNode getCastSpec(RelDataType type) {
+    switch (type.getSqlTypeName()) {
+    case TIMESTAMP:
+      return new SqlDataTypeSpec(
+          new SqlAlienSystemTypeNameSpec(
+              "DATETIME",
+              type.getSqlTypeName(),
+              SqlParserPos.ZERO),
+          SqlParserPos.ZERO);
+    default:
+      return super.getCastSpec(type);
+    }
+  }
+
+  @Override public void unparseDateTimeLiteral(SqlWriter writer,
+      SqlAbstractDateTimeLiteral literal, int leftPrec, int rightPrec) {
+    if (literal.getTypeName() == SqlTypeName.TIMESTAMP) {
+      writer.literal("DATETIME '" + literal.toFormattedString() + "'");
+    } else {
+      super.unparseDateTimeLiteral(writer, literal, leftPrec, rightPrec);
+    }
+  }
+
+}