branch-4.1: [fix](fe) Allow show tablet without selected database #63280 (#63512)

Cherry-picked from #63280

Co-authored-by: minghong <zhouminghong@selectdb.com>

Author: github-actions[bot]

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

@@ -46,7 +46,6 @@
 import org.apache.doris.statistics.query.QueryStatsUtil;
 
 import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.Strings;
 import com.google.common.collect.Lists;
 
 import java.util.List;
@@ -56,7 +55,6 @@
  */
 public class ShowTabletIdCommand extends ShowCommand {
     private final long tabletId;
-    private String dbName;
 
     /**
      * constructor
@@ -97,11 +95,6 @@ protected void validate(ConnectContext ctx) throws AnalysisException {
         if (!Env.getCurrentEnv().getAccessManager().checkGlobalPriv(ConnectContext.get(), PrivPredicate.ADMIN)) {
             ErrorReport.reportAnalysisException(ErrorCode.ERR_SPECIFIC_ACCESS_DENIED_ERROR, "SHOW TABLET");
         }
-
-        dbName = ctx.getDatabase();
-        if (Strings.isNullOrEmpty(dbName)) {
-            ErrorReport.reportAnalysisException(ErrorCode.ERR_NO_DB_ERROR);
-        }
     }
 
     private ShowResultSet handleShowTabletId() {

fe/fe-core/src/test/java/org/apache/doris/nereids/trees/plans/commands/ShowTabletIdCommandTest.java

@@ -78,9 +78,9 @@ void noGlobalPriv() {
     }
 
     @Test
-    void dbIsEmpty() {
+    void noDatabaseSelected() {
         runBefore("", true);
         ShowTabletIdCommand command = new ShowTabletIdCommand(CatalogMocker.TEST_TBL_ID);
-        Assertions.assertThrows(AnalysisException.class, () -> command.validate(ctx));
+        Assertions.assertDoesNotThrow(() -> command.validate(ctx));
     }
 }

regression-test/suites/show_p0/test_show_tablet.groovy

@@ -27,6 +27,12 @@ suite("test_show_tablet") {
             );"""
 
     def res = sql """ SHOW TABLETS FROM show_tablets_test_t """
+    def noDbJdbcUrl = context.config.jdbcUrl.replaceFirst(/(jdbc:mysql:\/\/[^\/]+\/)[^?]*/, '$1')
+    connect(context.config.jdbcUser, context.config.jdbcPassword, noDbJdbcUrl) {
+        def tabletId = res[0][0]
+        def tabletRes = sql """ SHOW TABLET ${tabletId} """
+        assertTrue(tabletRes.size() == 1)
+    }
     if (res.size() == 5) {
         // replication num == 1
         res = sql """SHOW TABLETS FROM show_tablets_test_t limit 5, 1;"""
@@ -53,4 +59,4 @@ suite("test_show_tablet") {
     } else {
         assertTrue(1 == 2)
     }
-}
+}