[Enhancement] (nereids)implement showCreateViewCommand in nereids

fe/fe-core/src/main/antlr4/org/apache/doris/nereids/DorisParser.g4

@@ -230,6 +230,7 @@ supportedShowStatement
     | SHOW STORAGE? ENGINES                                                         #showStorageEngines
     | SHOW CREATE CATALOG name=identifier                                           #showCreateCatalog
     | SHOW SQL_BLOCK_RULE (FOR ruleName=identifier)?                                #showSqlBlockRule
+    | SHOW CREATE VIEW name=multipartIdentifier                                     #showCreateView
     | SHOW CREATE MATERIALIZED VIEW mvName=identifier
         ON tableName=multipartIdentifier                                            #showCreateMaterializedView   
     | SHOW BACKENDS                                                                 #showBackends
@@ -285,7 +286,6 @@ unsupportedShowStatement
     | SHOW FULL? PROCESSLIST                                                        #showProcessList
     | SHOW (GLOBAL | SESSION | LOCAL)? STATUS wildWhere?                            #showStatus
     | SHOW EVENTS ((FROM | IN) database=multipartIdentifier)? wildWhere?            #showEvents
-    | SHOW CREATE VIEW name=multipartIdentifier                                     #showCreateView
     | SHOW CREATE MATERIALIZED VIEW name=multipartIdentifier                        #showMaterializedView
     | SHOW CREATE (DATABASE | SCHEMA) name=multipartIdentifier                      #showCreateDatabase
     | SHOW CREATE (GLOBAL | SESSION | LOCAL)? FUNCTION functionIdentifier

fe/fe-core/src/main/java/org/apache/doris/nereids/parser/LogicalPlanBuilder.java

@@ -214,6 +214,7 @@
 import org.apache.doris.nereids.DorisParser.ShowCreateMaterializedViewContext;
 import org.apache.doris.nereids.DorisParser.ShowCreateProcedureContext;
 import org.apache.doris.nereids.DorisParser.ShowCreateTableContext;
+import org.apache.doris.nereids.DorisParser.ShowCreateViewContext;
 import org.apache.doris.nereids.DorisParser.ShowDeleteContext;
 import org.apache.doris.nereids.DorisParser.ShowDynamicPartitionContext;
 import org.apache.doris.nereids.DorisParser.ShowFrontendsContext;
@@ -487,6 +488,7 @@
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateMaterializedViewCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateProcedureCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateTableCommand;
+import org.apache.doris.nereids.trees.plans.commands.ShowCreateViewCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowDeleteCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowDynamicPartitionCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowFrontendsCommand;
@@ -4297,6 +4299,12 @@ public LogicalPlan visitShowCreateTable(ShowCreateTableContext ctx) {
         return new ShowCreateTableCommand(new TableNameInfo(nameParts), ctx.BRIEF() != null);
     }
 
+    @Override
+    public LogicalPlan visitShowCreateView(ShowCreateViewContext ctx) {
+        List<String> nameParts = visitMultipartIdentifier(ctx.name);
+        return new ShowCreateViewCommand(new TableNameInfo(nameParts));
+    }
+
     @Override
     public LogicalPlan visitShowCreateMaterializedView(ShowCreateMaterializedViewContext ctx) {
         List<String> nameParts = visitMultipartIdentifier(ctx.tableName);
@@ -4369,6 +4377,7 @@ public RecoverPartitionCommand visitRecoverPartition(RecoverPartitionContext ctx
     }
 
     @Override
+
     public LogicalPlan visitShowBroker(ShowBrokerContext ctx) {
         return new ShowBrokerCommand();
     }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/PlanType.java

@@ -194,6 +194,7 @@ public enum PlanType {
     SHOW_CREATE_CATALOG_COMMAND,
     SHOW_CREATE_MATERIALIZED_VIEW_COMMAND,
     SHOW_CREATE_TABLE_COMMAND,
+    SHOW_CREATE_VIEW_COMMAND,
     SHOW_DELETE_COMMAND,
     SHOW_DYNAMIC_PARTITION_COMMAND,
     SHOW_FRONTENDS_COMMAND,

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/commands/ShowCreateViewCommand.java

@@ -0,0 +1,126 @@
+// 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.doris.nereids.trees.plans.commands;
+
+import org.apache.doris.catalog.Column;
+import org.apache.doris.catalog.DatabaseIf;
+import org.apache.doris.catalog.Env;
+import org.apache.doris.catalog.MTMV;
+import org.apache.doris.catalog.ScalarType;
+import org.apache.doris.catalog.TableIf;
+import org.apache.doris.catalog.View;
+import org.apache.doris.common.AnalysisException;
+import org.apache.doris.common.ErrorCode;
+import org.apache.doris.common.ErrorReport;
+import org.apache.doris.mysql.privilege.PrivPredicate;
+import org.apache.doris.nereids.trees.plans.PlanType;
+import org.apache.doris.nereids.trees.plans.commands.info.TableNameInfo;
+import org.apache.doris.nereids.trees.plans.visitor.PlanVisitor;
+import org.apache.doris.qe.ConnectContext;
+import org.apache.doris.qe.ShowResultSet;
+import org.apache.doris.qe.ShowResultSetMetaData;
+import org.apache.doris.qe.StmtExecutor;
+
+import com.google.common.collect.Lists;
+
+import java.util.List;
+
+/**
+ * Represents the command for SHOW CREATE VIEW.
+ */
+public class ShowCreateViewCommand extends ShowCommand {
+    private static final ShowResultSetMetaData VIEW_META_DATA =
+            ShowResultSetMetaData.builder()
+                    .addColumn(new Column("View", ScalarType.createVarchar(20)))
+                    .addColumn(new Column("Create View", ScalarType.createVarchar(30)))
+                    .addColumn(new Column("character_set_client", ScalarType.createVarchar(30)))
+                    .addColumn(new Column("collation_connection", ScalarType.createVarchar(30)))
+                    .build();
+
+    private final TableNameInfo tblNameInfo;
+
+    public ShowCreateViewCommand(TableNameInfo tableNameInfo) {
+        super(PlanType.SHOW_CREATE_VIEW_COMMAND);
+        this.tblNameInfo = tableNameInfo;
+    }
+
+    private void validate(ConnectContext ctx) throws AnalysisException {
+        tblNameInfo.analyze(ctx);
+
+        TableIf tableIf = Env.getCurrentEnv().getCatalogMgr()
+                .getCatalogOrAnalysisException(tblNameInfo.getCtl())
+                .getDbOrAnalysisException(tblNameInfo.getDb()).getTableOrAnalysisException(tblNameInfo.getTbl());
+
+        if (tableIf instanceof MTMV) {
+            ErrorReport.reportAnalysisException("not support async materialized view, "
+                    + "please use `show create materialized view`");
+        }
+
+        PrivPredicate wanted;
+        if (tableIf instanceof View) {
+            wanted = PrivPredicate.SHOW_VIEW;
+        } else {
+            wanted = PrivPredicate.SHOW;
+        }
+
+        if (!Env.getCurrentEnv().getAccessManager().checkTblPriv(ConnectContext.get(),
+                tblNameInfo.getCtl(), tblNameInfo.getDb(), tblNameInfo.getTbl(), wanted)) {
+            ErrorReport.reportAnalysisException(ErrorCode.ERR_TABLEACCESS_DENIED_ERROR, "SHOW CREATE TABLE",
+                                                ConnectContext.get().getQualifiedUser(),
+                                                ConnectContext.get().getRemoteIP(),
+                                                tblNameInfo.getDb() + ": " + tblNameInfo.getTbl());
+        }
+    }
+
+    @Override
+    public <R, C> R accept(PlanVisitor<R, C> visitor, C context) {
+        return visitor.visitShowCreateViewCommand(this, context);
+    }
+
+    @Override
+    public ShowResultSet doRun(ConnectContext ctx, StmtExecutor executor) throws Exception {
+        validate(ctx);
+        // Fetch the catalog, database, and view metadata
+        DatabaseIf db = ctx.getEnv().getCatalogMgr().getCatalogOrAnalysisException(tblNameInfo.getCtl())
+                        .getDbOrMetaException(tblNameInfo.getDb());
+        TableIf view = db.getTableOrMetaException(tblNameInfo.getTbl());
+
+        if (!(view instanceof View)) {
+            ErrorReport.reportAnalysisException(ErrorCode.ERR_WRONG_OBJECT, tblNameInfo.getDb(), tblNameInfo.getTbl(),
+                        "VIEW", "Use 'SHOW CREATE TABLE '" + tblNameInfo.getTbl());
+        }
+
+        List<List<String>> rows = Lists.newArrayList();
+        // Lock the view to ensure consistent metadata access
+        view.readLock();
+        try {
+            List<String> createViewStmt = Lists.newArrayList();
+            ctx.getEnv().getDdlStmt(null, null, view, createViewStmt, null, null, false, true,
+                        false, -1L, false, false);
+
+            if (!createViewStmt.isEmpty()) {
+                rows.add(Lists.newArrayList(view.getName(), createViewStmt.get(0), "utf8mb4", "utf8mb4_0900_bin"));
+            }
+        } finally {
+            view.readUnlock();
+        }
+
+        // Set the result set and send it using the executor
+        return new ShowResultSet(VIEW_META_DATA, rows);
+    }
+}

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/visitor/CommandVisitor.java

@@ -73,6 +73,7 @@
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateMaterializedViewCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateProcedureCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateTableCommand;
+import org.apache.doris.nereids.trees.plans.commands.ShowCreateViewCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowDeleteCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowDynamicPartitionCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowFrontendsCommand;
@@ -375,6 +376,10 @@ default R visitShowCreateMaterializedViewCommand(ShowCreateMaterializedViewComma
         return visitCommand(showCreateMtlzViewCommand, context);
     }
 
+    default R visitShowCreateViewCommand(ShowCreateViewCommand showCreateViewCommand, C context) {
+        return visitCommand(showCreateViewCommand, context);
+    }
+
     default R visitAlterRoleCommand(AlterRoleCommand alterRoleCommand, C context) {
         return visitCommand(alterRoleCommand, context);
     }

regression-test/data/nereids_p0/show/test_show_create_view.out

@@ -0,0 +1,7 @@
+-- This file is automatically generated. You should know what you did if you want to edit this
+-- !cmd --
+view_show_create_view	CREATE VIEW `view_show_create_view` AS SELECT `internal`.`regression_test_nereids_p0_show`.`table_for_view_test`.`id`, `internal`.`regression_test_nereids_p0_show`.`table_for_view_test`.`name` FROM `internal`.`regression_test_nereids_p0_show`.`table_for_view_test`;	utf8mb4	utf8mb4_0900_bin
+
+-- !cmd --
+view_show_create_view_2	CREATE VIEW `view_show_create_view_2` AS SELECT `internal`.`regression_test_nereids_p0_show`.`table_for_view_test_2`.`key_field`, `internal`.`regression_test_nereids_p0_show`.`table_for_view_test_2`.`value` FROM `internal`.`regression_test_nereids_p0_show`.`table_for_view_test_2`;	utf8mb4	utf8mb4_0900_bin
+

regression-test/suites/nereids_p0/show/test_show_create_view.groovy

@@ -0,0 +1,76 @@
+// 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.
+
+suite("test_show_create_view", "query,arrow_flight_sql") {
+    String view_name = "view_show_create_view";
+    String table_name = "table_for_view_test";
+    try {
+        // Create a table for testing
+        sql """
+            CREATE TABLE IF NOT EXISTS ${table_name} (
+                id INT COMMENT "Primary key",
+                name STRING COMMENT "Name field"
+            )
+            DISTRIBUTED BY HASH(id) BUCKETS 5
+            PROPERTIES ("replication_num" = "1");
+        """
+
+        // Create a view based on the created table
+        sql """
+            CREATE VIEW IF NOT EXISTS ${view_name} AS
+            SELECT id, name FROM ${table_name}
+        """
+
+        // Execute the SHOW CREATE VIEW command
+        checkNereidsExecute("""show create view `${view_name}`;""")
+        qt_cmd("""show create view `${view_name}`;""")
+    } finally {
+        // Drop the view and table after testing
+        try_sql("DROP VIEW IF EXISTS `${view_name}`")
+        try_sql("DROP TABLE IF EXISTS `${table_name}`")
+    }
+
+    // Additional case: Create another view based on a different table
+    String view_name_2 = "view_show_create_view_2";
+    String table_name_2 = "table_for_view_test_2";
+    try {
+        // Create another table for testing
+        sql """
+            CREATE TABLE IF NOT EXISTS ${table_name_2} (
+                `key_field` INT COMMENT "Key field",
+                `value` STRING COMMENT "Value field"
+            )
+            DISTRIBUTED BY HASH(key_field) BUCKETS 3
+            PROPERTIES ("replication_num" = "1");
+        """
+
+        // Create a view based on the new table
+        sql """
+            CREATE VIEW IF NOT EXISTS ${view_name_2} AS
+            SELECT key_field, value FROM ${table_name_2}
+        """
+
+        // Execute the SHOW CREATE VIEW command for the new view
+        checkNereidsExecute("""show create view `${view_name_2}`;""")
+        qt_cmd("""show create view `${view_name_2}`;""")
+
+    } finally {
+        // Drop the view and table after testing
+        try_sql("DROP VIEW IF EXISTS `${view_name_2}`")
+        try_sql("DROP TABLE IF EXISTS `${table_name_2}`")
+    }
+}