From 4afe8e4a89b1b6a6ddf662a3972ccca8fcc5dd86 Mon Sep 17 00:00:00 2001
From: tiancaiamao <tiancaiamao@gmail.com>
Date: Wed, 27 Nov 2019 20:41:41 +0800
Subject: [PATCH] planner/core: raise 'No database selected' error for grant
 statement (#13745)

---
 planner/core/integration_test.go | 11 +++++++++++
 planner/core/planbuilder.go      |  5 +++++
 2 files changed, 16 insertions(+)

diff --git a/planner/core/integration_test.go b/planner/core/integration_test.go
index 68ee6aede09f4..2beb39b4b5bd3 100644
--- a/planner/core/integration_test.go
+++ b/planner/core/integration_test.go
@@ -15,8 +15,10 @@ package core_test
 
 import (
 	. "github.com/pingcap/check"
+	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/kv"
+	"github.com/pingcap/tidb/planner/core"
 	"github.com/pingcap/tidb/util/testkit"
 	"github.com/pingcap/tidb/util/testutil"
 )
@@ -253,3 +255,12 @@ func (s *testIntegrationSuite) TestPartitionTableStats(c *C) {
 		tk.MustQuery(tt).Check(testkit.Rows(output[i].Result...))
 	}
 }
+
+func (s *testIntegrationSuite) TestErrNoDB(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("create user test")
+	_, err := tk.Exec("grant select on test1111 to test@'%'")
+	c.Assert(errors.Cause(err), Equals, core.ErrNoDB)
+	tk.MustExec("use test")
+	tk.MustExec("grant select on test1111 to test@'%'")
+}
diff --git a/planner/core/planbuilder.go b/planner/core/planbuilder.go
index 479c1c2c99a61..7bda8b45dc120 100644
--- a/planner/core/planbuilder.go
+++ b/planner/core/planbuilder.go
@@ -1359,6 +1359,11 @@ func (b *PlanBuilder) buildSimple(node ast.StmtNode) (Plan, error) {
 		err := ErrSpecificAccessDenied.GenWithStackByArgs("CREATE USER")
 		b.visitInfo = appendVisitInfo(b.visitInfo, mysql.CreateUserPriv, "", "", "", err)
 	case *ast.GrantStmt:
+		if b.ctx.GetSessionVars().CurrentDB == "" && raw.Level.DBName == "" {
+			if raw.Level.Level == ast.GrantLevelTable {
+				return nil, ErrNoDB
+			}
+		}
 		b.visitInfo = collectVisitInfoFromGrantStmt(b.ctx, b.visitInfo, raw)
 	case *ast.GrantRoleStmt:
 		err := ErrSpecificAccessDenied.GenWithStackByArgs("GRANT ROLE")