executor,planner: support show create 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])
+	ErrTableIsNotView              = terror.ClassExecutor.New(mysql.ErrWrongObject, "'%s.%s' is not VIEW")
 )
 
 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:
@@ -746,6 +748,27 @@ 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 ErrTableIsNotView.GenWithStackByArgs(db.Name.O, tb.Meta().Name.O)
+	}
+
+	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))
 	}
@@ -1746,6 +1749,8 @@ 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: