Basic support for MERGE queries

kernel/sql-federation/core/src/main/java/org/apache/shardingsphere/sqlfederation/compiler/converter/SQLNodeConverterEngine.java

@@ -26,9 +26,11 @@
 import org.apache.shardingsphere.sql.parser.sql.common.statement.dml.InsertStatement;
 import org.apache.shardingsphere.sql.parser.sql.common.statement.dml.SelectStatement;
 import org.apache.shardingsphere.sql.parser.sql.common.statement.dml.UpdateStatement;
+import org.apache.shardingsphere.sql.parser.sql.common.statement.dml.MergeStatement;
 import org.apache.shardingsphere.sqlfederation.compiler.converter.statement.delete.DeleteStatementConverter;
 import org.apache.shardingsphere.sqlfederation.compiler.converter.statement.explain.ExplainStatementConverter;
 import org.apache.shardingsphere.sqlfederation.compiler.converter.statement.insert.InsertStatementConverter;
+import org.apache.shardingsphere.sqlfederation.compiler.converter.statement.merge.MergeStatementConverter;
 import org.apache.shardingsphere.sqlfederation.compiler.converter.statement.update.UpdateStatementConverter;
 import org.apache.shardingsphere.sqlfederation.exception.OptimizationSQLNodeConvertException;
 import org.apache.shardingsphere.sqlfederation.compiler.converter.statement.select.SelectStatementConverter;
@@ -62,6 +64,9 @@ public static SqlNode convert(final SQLStatement statement) {
         if (statement instanceof InsertStatement) {
             return new InsertStatementConverter().convert((InsertStatement) statement);
         }
+        if (statement instanceof MergeStatement) {
+            return new MergeStatementConverter().convert((MergeStatement) statement);
+        }
         throw new OptimizationSQLNodeConvertException(statement);
     }
 }

kernel/sql-federation/core/src/main/java/org/apache/shardingsphere/sqlfederation/compiler/converter/statement/merge/MergeStatementConverter.java

@@ -0,0 +1,40 @@
+/*
+ * 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.shardingsphere.sqlfederation.compiler.converter.statement.merge;
+
+import org.apache.calcite.sql.SqlMerge;
+import org.apache.calcite.sql.SqlNode;
+import org.apache.calcite.sql.parser.SqlParserPos;
+import org.apache.shardingsphere.sql.parser.sql.common.statement.dml.MergeStatement;
+import org.apache.shardingsphere.sqlfederation.compiler.converter.segment.expression.ExpressionConverter;
+import org.apache.shardingsphere.sqlfederation.compiler.converter.segment.from.TableConverter;
+import org.apache.shardingsphere.sqlfederation.compiler.converter.statement.SQLStatementConverter;
+
+/**
+ * Merge statement converter.
+ */
+public final class MergeStatementConverter implements SQLStatementConverter<MergeStatement, SqlNode> {
+
+    @Override
+    public SqlNode convert(final MergeStatement mergeStatement) {
+        SqlNode targetTable = new TableConverter().convert(mergeStatement.getTarget()).orElseThrow(IllegalStateException::new);
+        SqlNode condition = new ExpressionConverter().convert(mergeStatement.getExpression().getExpr()).get();
+        SqlNode sourceTable = new TableConverter().convert(mergeStatement.getSource()).orElseThrow(IllegalStateException::new);
+        return new SqlMerge(SqlParserPos.ZERO, targetTable, condition, sourceTable, null, null, null, null);
+    }
+}

test/it/optimizer/src/test/java/org/apache/shardingsphere/test/it/optimizer/converter/SQLNodeConverterEngineIT.java

@@ -66,6 +66,8 @@ class SQLNodeConverterEngineIT {
 
     private static final String INSERT_STATEMENT_PREFIX = "INSERT";
 
+    private static final String MERGE_STATEMENT_PREFIX = "MERGE";
+
     @ParameterizedTest(name = "{0} ({1}) -> {2}")
     @ArgumentsSource(TestCaseArgumentsProvider.class)
     void assertConvert(final String sqlCaseId, final SQLCaseType sqlCaseType, final String databaseType) {
@@ -111,7 +113,8 @@ private boolean isSupportedSQLCase(final InternalSQLParserTestParameter testPara
                     || testParam.getSqlCaseId().toUpperCase().startsWith(DELETE_STATEMENT_PREFIX)
                     || testParam.getSqlCaseId().toUpperCase().startsWith(EXPLAIN_STATEMENT_PREFIX)
                     || testParam.getSqlCaseId().toUpperCase().startsWith(UPDATE_STATEMENT_PREFIX)
-                    || testParam.getSqlCaseId().toUpperCase().startsWith(INSERT_STATEMENT_PREFIX);
+                    || testParam.getSqlCaseId().toUpperCase().startsWith(INSERT_STATEMENT_PREFIX)
+                    || testParam.getSqlCaseId().toUpperCase().startsWith(MERGE_STATEMENT_PREFIX);
         }
     }
 }

test/it/optimizer/src/test/resources/converter/merge.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ 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.
+  -->
+
+<sql-node-converter-test-cases>
+    <test-cases sql-case-id="merge_into_table_using_table" expected-sql="MERGE INTO &quot;people_target&quot; USING &quot;people_source&quot; ON &quot;people_target&quot;.&quot;person_id&quot; = &quot;people_source&quot;.&quot;person_id&quot;" db-types="Oracle" sql-case-types="LITERAL" />
+    <test-cases sql-case-id="merge_into_table_using_subquery_alias" expected-sql="MERGE INTO &quot;bonuses&quot; &quot;D&quot; USING (SELECT &quot;employee_id&quot;, &quot;salary&quot;, &quot;department_id&quot; FROM &quot;employees&quot; WHERE &quot;department_id&quot; = 80) &quot;S&quot; ON &quot;D&quot;.&quot;employee_id&quot; = &quot;S&quot;.&quot;employee_id&quot;" db-types="Oracle" sql-case-types="LITERAL" />
+</sql-node-converter-test-cases>