[Enhancement] (nereids)implement showCollationCommand in nereids

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

@@ -231,6 +231,7 @@ supportedShowStatement
     | SHOW FILE ((FROM | IN) database=multipartIdentifier)?                         #showSmallFiles 
     | SHOW STORAGE? ENGINES                                                         #showStorageEngines
     | SHOW CREATE CATALOG name=identifier                                           #showCreateCatalog
+    | SHOW COLLATION wildWhere?                                                     #showCollation
     | SHOW SQL_BLOCK_RULE (FOR ruleName=identifier)?                                #showSqlBlockRule
     | SHOW CREATE MATERIALIZED VIEW mvName=identifier
         ON tableName=multipartIdentifier                                            #showCreateMaterializedView   
@@ -300,7 +301,6 @@ unsupportedShowStatement
     | SHOW CATALOG name=identifier                                                  #showCatalog
     | SHOW FULL? (COLUMNS | FIELDS) (FROM | IN) tableName=multipartIdentifier
         ((FROM | IN) database=multipartIdentifier)? wildWhere?                      #showColumns
-    | SHOW COLLATION wildWhere?                                                     #showCollation
     | SHOW ((CHAR SET) | CHARSET) wildWhere?                                        #showCharset
     | SHOW COUNT LEFT_PAREN ASTERISK RIGHT_PAREN (WARNINGS | ERRORS)                #showWaringErrorCount
     | SHOW (WARNINGS | ERRORS) limitClause?                                         #showWaringErrors

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

@@ -218,6 +218,7 @@
 import org.apache.doris.nereids.DorisParser.ShowAuthorsContext;
 import org.apache.doris.nereids.DorisParser.ShowBackendsContext;
 import org.apache.doris.nereids.DorisParser.ShowBrokerContext;
+import org.apache.doris.nereids.DorisParser.ShowCollationContext;
 import org.apache.doris.nereids.DorisParser.ShowConfigContext;
 import org.apache.doris.nereids.DorisParser.ShowConstraintContext;
 import org.apache.doris.nereids.DorisParser.ShowCreateCatalogContext;
@@ -494,6 +495,7 @@
 import org.apache.doris.nereids.trees.plans.commands.ShowAuthorsCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowBackendsCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowBrokerCommand;
+import org.apache.doris.nereids.trees.plans.commands.ShowCollationCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowConfigCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowConstraintsCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateCatalogCommand;
@@ -4582,4 +4584,17 @@ public LogicalPlan visitShowTabletsBelong(ShowTabletsBelongContext ctx) {
         });
         return new ShowTabletsBelongCommand(tabletIdLists);
     }
+
+    @Override
+    public LogicalPlan visitShowCollation(ShowCollationContext ctx) {
+        String wild = null;
+        if (ctx.wildWhere() != null) {
+            if (ctx.wildWhere().LIKE() != null) {
+                wild = stripQuotes(ctx.wildWhere().STRING_LITERAL().getText());
+            } else if (ctx.wildWhere().WHERE() != null) {
+                wild = ctx.wildWhere().expression().getText();
+            }
+        }
+        return new ShowCollationCommand(wild);
+    }
 }

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

@@ -192,6 +192,7 @@ public enum PlanType {
     SHOW_BACKENDS_COMMAND,
     SHOW_BLOCK_RULE_COMMAND,
     SHOW_BROKER_COMMAND,
+    SHOW_COLLATION_COMMAND,
     SHOW_CONFIG_COMMAND,
     SHOW_CREATE_CATALOG_COMMAND,
     SHOW_CREATE_MATERIALIZED_VIEW_COMMAND,

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

@@ -0,0 +1,89 @@
+// 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.ScalarType;
+import org.apache.doris.nereids.trees.plans.PlanType;
+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 COLLATION
+ */
+public class ShowCollationCommand extends ShowCommand {
+    private static final ShowResultSetMetaData COLLATION_META_DATA =
+            ShowResultSetMetaData.builder()
+                    .addColumn(new Column("Collation", ScalarType.createVarchar(20)))
+                    .addColumn(new Column("Charset", ScalarType.createVarchar(20)))
+                    .addColumn(new Column("Id", ScalarType.createVarchar(10)))
+                    .addColumn(new Column("Default", ScalarType.createVarchar(10)))
+                    .addColumn(new Column("Compiled", ScalarType.createVarchar(10)))
+                    .addColumn(new Column("Sortlen", ScalarType.createVarchar(10)))
+                    .build();
+
+    private final String wild;
+
+    public ShowCollationCommand(String wild) {
+        super(PlanType.SHOW_COLLATION_COMMAND);
+        this.wild = wild;
+    }
+
+    @Override
+    public ShowResultSet doRun(ConnectContext ctx, StmtExecutor executor) throws Exception {
+        List<List<String>> rows = Lists.newArrayList();
+        List<String> utf8mb40900Bin = Lists.newArrayList();
+        // | utf8mb4_0900_bin | utf8mb4 | 309 | Yes | Yes | 1 |
+        utf8mb40900Bin.add(ctx.getSessionVariable().getCollationConnection());
+        utf8mb40900Bin.add(ctx.getSessionVariable().getCharsetServer());
+        utf8mb40900Bin.add("309");
+        utf8mb40900Bin.add("Yes");
+        utf8mb40900Bin.add("Yes");
+        utf8mb40900Bin.add("1");
+        rows.add(utf8mb40900Bin);
+        // ATTN: we must have this collation for compatible with some bi tools
+        List<String> utf8mb3GeneralCi = Lists.newArrayList();
+        // | utf8mb3_general_ci | utf8mb3 | 33 | Yes | Yes | 1 |
+        utf8mb3GeneralCi.add("utf8mb3_general_ci");
+        utf8mb3GeneralCi.add("utf8mb3");
+        utf8mb3GeneralCi.add("33");
+        utf8mb3GeneralCi.add("Yes");
+        utf8mb3GeneralCi.add("Yes");
+        utf8mb3GeneralCi.add("1");
+        rows.add(utf8mb3GeneralCi);
+        // Set the result set and send it using the executor
+        return new ShowResultSet(COLLATION_META_DATA, rows);
+    }
+
+    @Override
+    public <R, C> R accept(PlanVisitor<R, C> visitor, C context) {
+        return visitor.visitShowCollationCommand(this, context);
+    }
+
+    @Override
+    public String toString() {
+        return "SHOW COLLATION" + (wild != null ? " LIKE '" + wild + "'" : "");
+    }
+}

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

@@ -68,6 +68,7 @@
 import org.apache.doris.nereids.trees.plans.commands.ShowAuthorsCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowBackendsCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowBrokerCommand;
+import org.apache.doris.nereids.trees.plans.commands.ShowCollationCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowConfigCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowConstraintsCommand;
 import org.apache.doris.nereids.trees.plans.commands.ShowCreateCatalogCommand;
@@ -475,6 +476,10 @@ default R visitShowTabletsBelongCommand(ShowTabletsBelongCommand showTabletBelon
         return visitCommand(showTabletBelongCommand, context);
     }
 
+    default R visitShowCollationCommand(ShowCollationCommand showCollationCommand, C context) {
+        return visitCommand(showCollationCommand, context);
+    }
+
     default R visitCreateRoutineLoadCommand(CreateRoutineLoadCommand createRoutineLoadCommand, C context) {
         return visitCommand(createRoutineLoadCommand, context);
     }

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

@@ -0,0 +1,5 @@
+-- This file is automatically generated. You should know what you did if you want to edit this
+-- !cmd --
+utf8mb4_0900_bin	utf8mb4	309	Yes	Yes	1
+utf8mb3_general_ci	utf8mb3	33	Yes	Yes	1
+

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

@@ -0,0 +1,29 @@
+// 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_collation", "query,collation") {
+    try {
+        // Execute the SHOW COLLATION command and verify the output
+        checkNereidsExecute("SHOW COLLATION")
+        qt_cmd("SHOW COLLATION")
+    } catch (Exception e) {
+        // Log any exceptions that occur during testing
+        log.error("Failed to execute SHOW COLLATION command", e)
+        throw e
+    }
+}
+