Add mariadb examples

docs/progs/mariadb.md

@@ -16,5 +16,9 @@ done
 
 ## Append field in table
 ```sql
-ALTER TABLE existsTableName ADD COLUMN `newFieldName` varchar(64) NOT NULL DEFAULT '';
+CREATE TABLE tableName_new AS (SELECT * FROM tableName);
+
+ALTER TABLE tableName_new ADD COLUMN `newFieldName` varchar(64) NOT NULL DEFAULT '' AFTER `existFieldName`;
+
+RENAME TABLE tableName TO tableName_old; RENAME TABLE tableName_new TO tableName;
 ```