executor,planner: support show create view

ddl/ddl.go

@@ -203,10 +203,8 @@ var (
 	ErrCoalesceOnlyOnHashPartition = terror.ClassDDL.New(codeCoalesceOnlyOnHashPartition, mysql.MySQLErrName[mysql.ErrCoalesceOnlyOnHashPartition])
 	// ErrViewWrongList returns create view must include all columns in the select clause
 	ErrViewWrongList = terror.ClassDDL.New(codeViewWrongList, mysql.MySQLErrName[mysql.ErrViewWrongList])
-	// ErrTableIsNotView returns for table is not view.
-	ErrTableIsNotView = terror.ClassDDL.New(codeErrWrongObject, "'%s.%s' is not VIEW")
-	// ErrTableIsNotBaseTable returns for table is not base table.
-	ErrTableIsNotBaseTable = terror.ClassDDL.New(codeErrWrongObject, "'%s.%s' is not BASE TABLE")
+	// ErrWrongObject returns for wrong object.
+	ErrWrongObject = terror.ClassDDL.New(codeErrWrongObject, mysql.MySQLErrName[mysql.ErrWrongObject])
 )
 
 // DDL is responsible for updating schema in data store and maintaining in-memory InfoSchema cache.

ddl/ddl_api.go

@@ -1179,7 +1179,7 @@ func (d *ddl) CreateView(ctx sessionctx.Context, s *ast.CreateViewStmt) (err err
 	var oldViewTblID int64
 	if oldView != nil {
 		if !oldView.Meta().IsView() {
-			return ErrTableIsNotView.GenWithStackByArgs(ident.Schema, ident.Name)
+			return ErrWrongObject.GenWithStackByArgs(ident.Schema, ident.Name, "VIEW")
 		}
 		oldViewTblID = oldView.Meta().ID
 	}
@@ -1442,7 +1442,7 @@ func (d *ddl) AlterTable(ctx sessionctx.Context, ident ast.Ident, specs []*ast.A
 
 	is := d.infoHandle.Get()
 	if is.TableIsView(ident.Schema, ident.Name) {
-		return ErrTableIsNotBaseTable.GenWithStackByArgs(ident.Schema, ident.Name)
+		return ErrWrongObject.GenWithStackByArgs(ident.Schema, ident.Name, "BASE TABLE")
 	}
 
 	for _, spec := range validSpecs {
@@ -2406,7 +2406,7 @@ func (d *ddl) DropView(ctx sessionctx.Context, ti ast.Ident) (err error) {
 	}
 
 	if !tb.Meta().IsView() {
-		return ErrTableIsNotView.GenWithStackByArgs(ti.Schema, ti.Name)
+		return ErrWrongObject.GenWithStackByArgs(ti.Schema, ti.Name, "VIEW")
 	}
 
 	job := &model.Job{

executor/ddl_test.go

@@ -185,7 +185,7 @@ func (s *testSuite3) TestCreateView(c *C) {
 	tk.MustExec("create or replace view v1 (c,d) as select a,b from t1 ")
 	tk.MustExec("create table if not exists t1 (a int ,b int)")
 	_, err = tk.Exec("create or replace view t1 as select * from t1")
-	c.Assert(err.Error(), Equals, ddl.ErrTableIsNotView.GenWithStackByArgs("test", "t1").Error())
+	c.Assert(err.Error(), Equals, ddl.ErrWrongObject.GenWithStackByArgs("test", "t1", "VIEW").Error())
 }
 
 func (s *testSuite3) TestCreateDropDatabase(c *C) {
@@ -264,7 +264,7 @@ func (s *testSuite3) TestAlterTableAddColumn(c *C) {
 	tk.MustQuery("select c3 from alter_test").Check(testkit.Rows("CURRENT_TIMESTAMP"))
 	tk.MustExec("create or replace view alter_view as select c1,c2 from alter_test")
 	_, err = tk.Exec("alter table alter_view add column c4 varchar(50)")
-	c.Assert(err.Error(), Equals, ddl.ErrTableIsNotBaseTable.GenWithStackByArgs("test", "alter_view").Error())
+	c.Assert(err.Error(), Equals, ddl.ErrWrongObject.GenWithStackByArgs("test", "alter_view", "BASE TABLE").Error())
 	tk.MustExec("drop view alter_view")
 }
 
@@ -312,7 +312,7 @@ func (s *testSuite3) TestAlterTableModifyColumn(c *C) {
 	c.Assert(createSQL, Equals, expected)
 	tk.MustExec("create or replace view alter_view as select c1,c2 from mc")
 	_, err = tk.Exec("alter table alter_view modify column c2 text")
-	c.Assert(err.Error(), Equals, ddl.ErrTableIsNotBaseTable.GenWithStackByArgs("test", "alter_view").Error())
+	c.Assert(err.Error(), Equals, ddl.ErrWrongObject.GenWithStackByArgs("test", "alter_view", "BASE TABLE").Error())
 	tk.MustExec("drop view alter_view")
 }
 

executor/errors.go

@@ -48,6 +48,7 @@ var (
 	ErrDBaccessDenied              = terror.ClassExecutor.New(mysql.ErrDBaccessDenied, mysql.MySQLErrName[mysql.ErrDBaccessDenied])
 	ErrTableaccessDenied           = terror.ClassExecutor.New(mysql.ErrTableaccessDenied, mysql.MySQLErrName[mysql.ErrTableaccessDenied])
 	ErrBadDB                       = terror.ClassExecutor.New(mysql.ErrBadDB, mysql.MySQLErrName[mysql.ErrBadDB])
+	ErrWrongObject                 = terror.ClassExecutor.New(mysql.ErrWrongObject, mysql.MySQLErrName[mysql.ErrWrongObject])
 )
 
 func init() {
@@ -63,6 +64,7 @@ func init() {
 		mysql.ErrDBaccessDenied:              mysql.ErrDBaccessDenied,
 		mysql.ErrTableaccessDenied:           mysql.ErrTableaccessDenied,
 		mysql.ErrBadDB:                       mysql.ErrBadDB,
+		mysql.ErrWrongObject:                 mysql.ErrWrongObject,
 	}
 	terror.ErrClassToMySQLCodes[terror.ClassExecutor] = tableMySQLErrCodes
 }

executor/show.go

@@ -107,6 +107,8 @@ func (e *ShowExec) fetchAll() error {
 		return e.fetchShowColumns()
 	case ast.ShowCreateTable:
 		return e.fetchShowCreateTable()
+	case ast.ShowCreateView:
+		return e.fetchShowCreateView()
 	case ast.ShowCreateDatabase:
 		return e.fetchShowCreateDatabase()
 	case ast.ShowDatabases:
@@ -764,6 +766,27 @@ func (e *ShowExec) fetchShowCreateTable() error {
 	return nil
 }
 
+func (e *ShowExec) fetchShowCreateView() error {
+	db, ok := e.is.SchemaByName(e.DBName)
+	if !ok {
+		return infoschema.ErrDatabaseNotExists.GenWithStackByArgs(e.DBName.O)
+	}
+
+	tb, err := e.getTable()
+	if err != nil {
+		return errors.Trace(err)
+	}
+
+	if !tb.Meta().IsView() {
+		return ErrWrongObject.GenWithStackByArgs(db.Name.O, tb.Meta().Name.O, "VIEW")
+	}
+
+	var buf bytes.Buffer
+	e.fetchShowCreateTable4View(tb.Meta(), &buf)
+	e.appendRow([]interface{}{tb.Meta().Name.O, buf.String(), tb.Meta().Charset, tb.Meta().Collate})
+	return nil
+}
+
 func (e *ShowExec) fetchShowCreateTable4View(tb *model.TableInfo, buf *bytes.Buffer) {
 	sqlMode := e.ctx.GetSessionVars().SQLMode
 

executor/show_test.go

@@ -309,6 +309,7 @@ func (s *testSuite2) TestShowCreateTable(c *C) {
 	tk.MustExec("drop view if exists v1")
 	tk.MustExec("create or replace definer=`root`@`127.0.0.1` view v1 as select * from t1")
 	tk.MustQuery("show create table v1").Check(testutil.RowsWithSep("|", "v1|CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`127.0.0.1` SQL SECURITY DEFINER VIEW `v1` (`a`, `b`) AS select * from t1  "))
+	tk.MustQuery("show create view v1").Check(testutil.RowsWithSep("|", "v1|CREATE ALGORITHM=UNDEFINED DEFINER=`root`@`127.0.0.1` SQL SECURITY DEFINER VIEW `v1` (`a`, `b`) AS select * from t1  "))
 
 	tk.MustExec("drop view v1")
 	tk.MustExec("drop table t1")

planner/core/planbuilder.go

@@ -969,6 +969,9 @@ func (b *PlanBuilder) buildShow(show *ast.ShowStmt) (Plan, error) {
 			if table, err := b.is.TableByName(show.Table.Schema, show.Table.Name); err == nil {
 				isView = table.Meta().IsView()
 			}
+		case ast.ShowCreateView:
+			err := ErrSpecificAccessDenied.GenWithStackByArgs("SHOW VIEW")
+			b.visitInfo = appendVisitInfo(b.visitInfo, mysql.ShowViewPriv, "", "", "", err)
 		}
 		p.SetSchema(buildShowSchema(show, isView))
 	}
@@ -1744,6 +1747,8 @@ func buildShowSchema(s *ast.ShowStmt, isView bool) (schema *expression.Schema) {
 		} else {
 			names = []string{"View", "Create View", "character_set_client", "collation_connection"}
 		}
+	case ast.ShowCreateView:
+		names = []string{"View", "Create View", "character_set_client", "collation_connection"}
 	case ast.ShowCreateDatabase:
 		names = []string{"Database", "Create Database"}
 	case ast.ShowGrants: