diff --git a/apps/desktop/src/lib/__tests__/sql/sqlCompletionLookupTarget.spec.ts b/apps/desktop/src/lib/__tests__/sql/sqlCompletionLookupTarget.spec.ts
index 70860ea521..4c800a424b 100644
--- a/apps/desktop/src/lib/__tests__/sql/sqlCompletionLookupTarget.spec.ts
+++ b/apps/desktop/src/lib/__tests__/sql/sqlCompletionLookupTarget.spec.ts
@@ -12,6 +12,8 @@ import {
   sqlServerLeadingUseScript,
   sqlServerUseCompletionDatabaseNames,
   sqlServerUseDatabaseFromStatement,
+  switchesDatabaseWithUseStatement,
+  useDatabaseFromStatement,
 } from "@/lib/sql/sqlCompletionLookupTarget";
 
 describe("sqlCompletionLookupTarget", () => {
@@ -290,6 +292,35 @@ describe("sqlCompletionLookupTarget", () => {
     expect(sqlServerLeadingUseScript("USE FooDB; INSERT INTO audit_log VALUES (1); SELECT * FROM Users;")).toBeUndefined();
   });
 
+  it("parses the USE target of MySQL-family dialects in all three identifier forms", () => {
+    expect(useDatabaseFromStatement("USE hd_ods", "mysql")).toBe("hd_ods");
+    expect(useDatabaseFromStatement("use hd_ods;", "mysql")).toBe("hd_ods");
+    expect(useDatabaseFromStatement("  USE `hd-ods`;  ", "doris")).toBe("hd-ods");
+    expect(useDatabaseFromStatement('USE "报告库";', "starrocks")).toBe("报告库");
+    expect(useDatabaseFromStatement("-- switch\n/* c */ USE goldendb_db;", "goldendb")).toBe("goldendb_db");
+    expect(useDatabaseFromStatement("USE `a``b`;", "gbase")).toBe("a`b");
+  });
+
+  it("does not turn other statements or dialects into a database switch", () => {
+    expect(useDatabaseFromStatement("SELECT 1 FROM dual;", "mysql")).toBeUndefined();
+    expect(useDatabaseFromStatement("USE hd_ods; SELECT 1;", "mysql")).toBeUndefined();
+    expect(useDatabaseFromStatement("USE hd_ods;", "postgres")).toBeUndefined();
+    expect(useDatabaseFromStatement("USE other_ods;", "oracle")).toBeUndefined();
+    // SQL Server keeps its own bracket-aware parser.
+    expect(useDatabaseFromStatement("USE [Bar]]DB];", "sqlserver")).toBe("Bar]DB");
+    expect(useDatabaseFromStatement("USE hd_ods;", undefined)).toBeUndefined();
+  });
+
+  it("reports which dialects treat USE as a database switch", () => {
+    for (const databaseType of ["mysql", "doris", "starrocks", "goldendb", "gbase"] as const) {
+      expect(switchesDatabaseWithUseStatement(databaseType)).toBe(true);
+    }
+    for (const databaseType of ["postgres", "oracle", "clickhouse", "hive"] as const) {
+      expect(switchesDatabaseWithUseStatement(databaseType)).toBe(false);
+    }
+    expect(switchesDatabaseWithUseStatement(undefined)).toBe(false);
+  });
+
   it("ignores commented, quoted, current, later, and non-SQL Server USE text", () => {
     const sql = "-- USE [CommentDB]\nSELECT 'USE [StringDB]';\nSELECT * FROM T;\nUSE [LaterDB];";
     const cursor = sql.indexOf("T;") + 1;
diff --git a/apps/desktop/src/lib/sql/sqlCompletionLookupTarget.ts b/apps/desktop/src/lib/sql/sqlCompletionLookupTarget.ts
index 37dcdfae63..7f2501aeae 100644
--- a/apps/desktop/src/lib/sql/sqlCompletionLookupTarget.ts
+++ b/apps/desktop/src/lib/sql/sqlCompletionLookupTarget.ts
@@ -54,6 +54,32 @@ export function sqlServerUseDatabaseFromStatement(statement: string): string | u
   return match[3];
 }
 
+/**
+ * 方言里 `USE <db>` 会把会话切到另一个库，DBX 的标签库名应当跟着走（#9941）。
+ *
+ * 只列出已经确认过这一语义的方言：MySQL 及其 wire-protocol 家族。SQL Server 由
+ * `sqlServerUseDatabaseFromStatement` 单独处理（它还接受 `[db]` 括号标识符）。
+ */
+const USE_DATABASE_SWITCH_DIALECTS: ReadonlySet<DatabaseType> = new Set<DatabaseType>(["mysql", "doris", "starrocks", "goldendb", "gbase"]);
+
+export function switchesDatabaseWithUseStatement(databaseType: DatabaseType | null | undefined): boolean {
+  return !!databaseType && USE_DATABASE_SWITCH_DIALECTS.has(databaseType);
+}
+
+/**
+ * 解析单条语句里「成功切换当前库」的 `USE <db>`，返回目标库名（反引号、双引号或裸
+ * 标识符）。不是 USE 语句、或该方言的 USE 不改库时返回 undefined。
+ */
+export function useDatabaseFromStatement(statement: string, databaseType?: DatabaseType): string | undefined {
+  if (databaseType === "sqlserver") return sqlServerUseDatabaseFromStatement(statement);
+  if (!switchesDatabaseWithUseStatement(databaseType)) return undefined;
+  const match = /^USE\s+(?:`((?:[^`]|``)*)`|"((?:[^"]|"")*)"|([\p{L}_$][\p{L}\p{N}_$]*))\s*;?\s*$/iu.exec(sqlStatementWithoutLeadingComments(statement));
+  if (!match) return undefined;
+  if (match[1] !== undefined) return match[1].replaceAll("``", "`");
+  if (match[2] !== undefined) return match[2].replaceAll('""', '"');
+  return match[3];
+}
+
 export function sqlServerUseDatabaseBeforeCursor(sql: string, cursor: number): string | undefined {
   const position = Math.max(0, Math.min(cursor, sql.length));
   let database: string | undefined;
diff --git a/apps/desktop/src/stores/__tests__/queryStore.useDatabaseStatement.spec.ts b/apps/desktop/src/stores/__tests__/queryStore.useDatabaseStatement.spec.ts
new file mode 100644
index 0000000000..52896c1d76
--- /dev/null
+++ b/apps/desktop/src/stores/__tests__/queryStore.useDatabaseStatement.spec.ts
@@ -0,0 +1,96 @@
+import { createPinia, setActivePinia } from "pinia";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { QueryResult } from "@/types/database";
+
+const mocks = vi.hoisted(() => ({
+  executeMulti: vi.fn(),
+  executeQuery: vi.fn(),
+  closeClientConnectionSession: vi.fn(),
+  saveOpenTabsState: vi.fn(),
+  preparePaginationPlan: vi.fn(),
+  getConfig: vi.fn(),
+  ensureConnected: vi.fn(),
+}));
+
+vi.mock("@/lib/backend/api", () => ({
+  executeMulti: mocks.executeMulti,
+  executeQuery: mocks.executeQuery,
+  closeClientConnectionSession: mocks.closeClientConnectionSession,
+  saveOpenTabsState: mocks.saveOpenTabsState,
+  prepareQueryPaginationExecutionPlan: mocks.preparePaginationPlan,
+}));
+
+vi.mock("@/stores/connectionStore", () => ({
+  useConnectionStore: () => ({
+    getConfig: mocks.getConfig,
+    ensureConnected: mocks.ensureConnected,
+    recordConnectionLostError: vi.fn(),
+  }),
+}));
+
+vi.mock("@/stores/settingsStore", () => ({
+  useSettingsStore: () => ({
+    editorSettings: { pageSize: 100, openTabsRestoreMode: "all", confirmUnsavedSqlClose: false },
+  }),
+}));
+
+const okResult: QueryResult = { columns: [], rows: [], affected_rows: 0, execution_time_ms: 1 };
+
+function installLocalStorage() {
+  const data = new Map<string, string>();
+  vi.stubGlobal("localStorage", {
+    getItem: vi.fn((key: string) => data.get(key) ?? null),
+    setItem: vi.fn((key: string, value: string) => data.set(key, value)),
+    removeItem: vi.fn((key: string) => data.delete(key)),
+  });
+}
+
+describe("queryStore USE database statement", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.unstubAllGlobals();
+    installLocalStorage();
+    setActivePinia(createPinia());
+    mocks.getConfig.mockReturnValue({ id: "mysql-1", name: "MySQL", db_type: "mysql", query_timeout_secs: 45 });
+    mocks.executeMulti.mockResolvedValue([okResult]);
+    mocks.executeQuery.mockResolvedValue(okResult);
+    mocks.closeClientConnectionSession.mockResolvedValue(true);
+    mocks.saveOpenTabsState.mockResolvedValue(undefined);
+    mocks.ensureConnected.mockResolvedValue(undefined);
+    mocks.preparePaginationPlan.mockImplementation(async (options: { sql: string }) => ({ sqlToExecute: options.sql }));
+  });
+
+  it("follows a successful USE statement in the tab's database", async () => {
+    const { useQueryStore } = await import("@/stores/queryStore");
+    const store = useQueryStore();
+    const tabId = store.createTab("mysql-1", "dbx", "Query", "query");
+
+    await store.executeTabSql(tabId, "USE dbx_dup;");
+
+    expect(mocks.executeMulti).toHaveBeenCalledTimes(1);
+    expect(store.tabs.find((tab) => tab.id === tabId)?.database).toBe("dbx_dup");
+    await vi.waitFor(() => expect(mocks.closeClientConnectionSession).toHaveBeenCalled());
+  });
+
+  it("keeps the tab on its database when the USE statement fails", async () => {
+    mocks.executeMulti.mockResolvedValue([{ ...okResult, execution_error: true }]);
+    const { useQueryStore } = await import("@/stores/queryStore");
+    const store = useQueryStore();
+    const tabId = store.createTab("mysql-1", "dbx", "Query", "query");
+
+    await store.executeTabSql(tabId, "USE missing_db;");
+
+    expect(store.tabs.find((tab) => tab.id === tabId)?.database).toBe("dbx");
+  });
+
+  it("does not follow USE for dialects where it is not a database switch", async () => {
+    mocks.getConfig.mockReturnValue({ id: "pg-1", name: "PostgreSQL", db_type: "postgres", query_timeout_secs: 45 });
+    const { useQueryStore } = await import("@/stores/queryStore");
+    const store = useQueryStore();
+    const tabId = store.createTab("pg-1", "public_db", "Query", "query");
+
+    await store.executeTabSql(tabId, "USE other_db;");
+
+    expect(store.tabs.find((tab) => tab.id === tabId)?.database).toBe("public_db");
+  });
+});
diff --git a/apps/desktop/src/stores/queryStore.ts b/apps/desktop/src/stores/queryStore.ts
index f83ec1c6d4..fd00b78131 100644
--- a/apps/desktop/src/stores/queryStore.ts
+++ b/apps/desktop/src/stores/queryStore.ts
@@ -67,7 +67,7 @@ import { normalizeResultPageSize } from "@/lib/dataGrid/paginationPageSize";
 import { agentProtocolQueryResultMaxRows, capQueryResultTotal, effectiveQueryResultMaxRows, limitQueryPagination, queryResultLimitReached } from "@/lib/dataGrid/queryResultRowLimit";
 import { elasticsearchRestRequestRanges, executableStatementRanges, splitSqlStatementRanges, sqlStatementParameterOptionsForCompatibility, stripMysqlClientDisplayCommand } from "@/lib/sql/sqlStatementRanges";
 import type { SqlParameterOptions } from "@/lib/sql/sqlParameters";
-import { replaceSqlServerLeadingUseQuery, sqlServerLeadingUseScript, sqlServerUseDatabaseFromStatement } from "@/lib/sql/sqlCompletionLookupTarget";
+import { replaceSqlServerLeadingUseQuery, sqlServerLeadingUseScript, switchesDatabaseWithUseStatement, useDatabaseFromStatement } from "@/lib/sql/sqlCompletionLookupTarget";
 import { classifySqlRisk } from "@/lib/sql/sqlRisk";
 import { externalSqlFileDisplayTitles, normalizeExternalSqlPath } from "@/lib/sql/sqlFileOpen";
 import { clearDataGridPendingSnapshot, clearDataGridPendingSnapshotsForTab } from "@/composables/useDataGridEditor";
@@ -369,16 +369,7 @@ function preservedResultIndex(results: QueryResult[], currentIndex: number | und
   return currentIndex;
 }
 
-function annotateQueryResultSources(
-  results: QueryResult[],
-  sql: string,
-  database: string | undefined,
-  databaseType?: DatabaseType,
-  sourceOffset?: number,
-  parameterOptions?: SqlParameterOptions,
-  executedSql?: string,
-  sourceDocumentSql?: string,
-): { results: QueryResult[]; sqlServerUseDatabase?: string } {
+function annotateQueryResultSources(results: QueryResult[], sql: string, database: string | undefined, databaseType?: DatabaseType, sourceOffset?: number, parameterOptions?: SqlParameterOptions, executedSql?: string, sourceDocumentSql?: string): { results: QueryResult[]; useDatabase?: string } {
   const statements = splitSqlStatementRanges(sql, databaseType, parameterOptions);
   // The backend positions errors against the SQL it actually received. When the
   // sent SQL was rewritten (pagination wrapper, injected hidden keys…), record
@@ -389,7 +380,7 @@ function annotateQueryResultSources(
   const documentStatements = sourceDocumentSql && sourceOffset !== undefined ? splitSqlStatementRanges(sourceDocumentSql, databaseType, parameterOptions) : [];
   let statementIndex = 0;
   let sourceDatabase = database;
-  let sqlServerUseDatabase: string | undefined;
+  let useDatabase: string | undefined;
   for (const result of results) {
     const explicitIndex = Number.isInteger(result.statement_index) && result.statement_index! >= 0 ? result.statement_index : undefined;
     const sourceIndex = explicitIndex ?? statementIndex;
@@ -420,13 +411,13 @@ function annotateQueryResultSources(
     const preamble = documentStatement ? sourceDocumentSql!.slice(documentStatement.hitFrom, documentStatement.from) : sql.slice(statement.hitFrom, statement.from);
     const customName = queryResultNameFromPreamble(preamble, { databaseType });
     if (customName) result.sourceLabel = customName;
-    const successfulUseDatabase = databaseType === "sqlserver" && result.execution_error !== true ? sqlServerUseDatabaseFromStatement(statement.sql) : undefined;
+    const successfulUseDatabase = result.execution_error !== true ? useDatabaseFromStatement(statement.sql, databaseType) : undefined;
     if (successfulUseDatabase) {
       sourceDatabase = successfulUseDatabase;
-      sqlServerUseDatabase = successfulUseDatabase;
+      useDatabase = successfulUseDatabase;
     }
   }
-  return { results, sqlServerUseDatabase };
+  return { results, useDatabase };
 }
 
 /**
@@ -7557,7 +7548,11 @@ export const useQueryStore = defineStore("query", () => {
       }
       const successfulOracleSchemaChanges = usesOracleStickyTransactionState(effectiveDbType) ? results.filter((result) => result.execution_error !== true && isOracleCurrentSchemaStatement(result.sourceStatement)).length : 0;
       const successfulSapHanaSchemaChanges = effectiveDbType === "saphana" ? results.filter((result) => result.execution_error !== true && isSapHanaSetSchemaStatement(result.sourceStatement)).length : 0;
-      const sqlServerUseDatabase = effectiveDbType === "sqlserver" ? annotatedResults.sqlServerUseDatabase : undefined;
+      const sqlServerUseDatabase = effectiveDbType === "sqlserver" ? annotatedResults.useDatabase : undefined;
+      // MySQL 家族（含 Doris/StarRocks）的 `USE db` 同样会切走会话的当前库，标签库名
+      // 要跟着走，否则工具栏、标签标题和侧栏仍指向旧库（#9941）。SQL Server 走上面的
+      // 分支，它有额外的事务与 reset 语义。
+      const mysqlUseDatabase = switchesDatabaseWithUseStatement(effectiveDbType) ? annotatedResults.useDatabase : undefined;
       if (hiddenPrimaryKeys.length > 0 && results.length === 1) {
         const hiddenIndexes = hiddenResultColumnIndexes(results[0]!.columns, hiddenPrimaryKeys);
         if (hiddenIndexes.length > 0) results[0]!.hidden_column_indexes = hiddenIndexes;
@@ -7601,6 +7596,16 @@ export const useQueryStore = defineStore("query", () => {
           current.database = sqlServerUseDatabase;
           current.schema = undefined;
         }
+        if (mysqlUseDatabase && !usesExternalExecutionTarget && current.database !== mysqlUseDatabase) {
+          // 切库后旧库的池（池按「连接 + 库」分桶）不再被这个标签复用，旧会话却已经在
+          // server 端停在新库上；不关掉它，用户切回旧库时会被重新用上，出现「标签写着 A、
+          // 实际在 B」的错配。标签上挂着的显式事务在切库后同样不可达，一并收掉（与 SQL
+          // Server 分支一致）。
+          rollbackTabTransaction(current);
+          void closeClientConnectionSession(current);
+          current.database = mysqlUseDatabase;
+          current.schema = undefined;
+        }
         const activeGroupIndex = current.activeResultIndex;
         const activeGroupResults = current.results;
         const shouldAppendResult = !!options?.appendResult && !!current.result;
diff --git a/docs/screenshots/issue-9941-after-back-to-dbx.png b/docs/screenshots/issue-9941-after-back-to-dbx.png
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diff --git a/docs/screenshots/issue-9941-before-session-dbx_dup-ui-still-dbx.png b/docs/screenshots/issue-9941-before-session-dbx_dup-ui-still-dbx.png
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