implement drop temporary table and display temporary tables

Author: James Cor

sql/planbuilder/ddl.go

@@ -253,6 +253,11 @@ func (b *Builder) buildDropTable(inScope *scope, c *ast.DDL) (outScope *scope) {
 
 		tableScope, ok := b.buildResolvedTableForTablename(inScope, t, nil)
 		if ok {
+			// attempting to drop a non-temporary table with DROP TEMPORARY, results in Unknown table
+			if _, isTmpTbl := tableScope.node.(sql.TemporaryTable); !isTmpTbl && c.Temporary {
+				err := sql.ErrUnknownTable.New(tableName)
+				b.handleErr(err)
+			}
 			dropTables = append(dropTables, tableScope.node)
 		} else if !c.IfExists {
 			err := sql.ErrTableNotFound.New(tableName)

sql/rowexec/show_iters.go

@@ -498,7 +498,12 @@ func (i *showCreateTablesIter) produceCreateTableStatement(ctx *sql.Context, tab
 		}
 	}
 
-	return sql.GenerateCreateTableStatement(table.Name(), colStmts, autoInc, table.Collation().CharacterSet().Name(), table.Collation().Name(), comment), nil
+	temp := ""
+	if _, ok := table.(sql.TemporaryTable); ok {
+		temp = " TEMPORARY"
+	}
+
+	return sql.GenerateCreateTableStatement(table.Name(), colStmts, temp, autoInc, table.Collation().CharacterSet().Name(), table.Collation().Name(), comment), nil
 }
 
 func produceCreateViewStatement(view *plan.SubqueryAlias) string {

sql/sqlfmt.go

@@ -26,7 +26,7 @@ import (
 
 // GenerateCreateTableStatement returns 'CREATE TABLE' statement with given table names
 // and column definition statements in order and the collation and character set names for the table
-func GenerateCreateTableStatement(tblName string, colStmts []string, autoInc, tblCharsetName, tblCollName, comment string) string {
+func GenerateCreateTableStatement(tblName string, colStmts []string, temp, autoInc, tblCharsetName, tblCollName, comment string) string {
 	if comment != "" {
 		// Escape any single quotes in the comment and add the COMMENT keyword
 		comment = strings.ReplaceAll(comment, "'", "''")
@@ -38,7 +38,8 @@ func GenerateCreateTableStatement(tblName string, colStmts []string, autoInc, tb
 	}
 
 	return fmt.Sprintf(
-		"CREATE TABLE %s (\n%s\n) ENGINE=InnoDB%s DEFAULT CHARSET=%s COLLATE=%s%s",
+		"CREATE%s TABLE %s (\n%s\n) ENGINE=InnoDB%s DEFAULT CHARSET=%s COLLATE=%s%s",
+		temp,
 		QuoteIdentifier(tblName),
 		strings.Join(colStmts, ",\n"),
 		autoInc,