mariadb
MariaDB Create Database
Written by georg on Oktober 23, 2019
Eine Datenbank anlegen geht ganz einfach
MariaDB [(none)]> create database db1; Query OK, 1 row affected (0.001 sec)
Außer es soll ein Bindestrich im Datenbanknamen vorkommen
MariaDB [(none)]> create database db-1; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '-1' at line 1
Vielleicht helfen Anführungszeichen
MariaDB [(none)]> create database "db-1"; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '"db-1"' at line 1
Oder einfache Hochkommata
MariaDB [(none)]> create database 'db-1'; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''db-1' at line 1
Oder mit einem Schrägstrich quotieren
MariaDB [(none)]> create database 'db\-1'; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''db\-'' at line 1
Oder so was
MariaDB [(none)]> create database ´db-1´; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '-1´' t line 1
Nein, es müssen Backticks sein
MariaDB [(none)]> create database `db-1`; Query OK, 1 row affected (0.001 sec)
Ist doch logisch!?
SQL NULL-SAFE
Written by georg on August 6, 2019
Liefert keine Felder zurück, wo eines oder beide Felder NULL sind:
select usr_id from usr_data where (usr_data.a != usr_data.b);
NULL-SAFE – schlägt auch an, wenn eines der Felder NULL ist:
select usr_id from usr_data where NOT (usr_data.a <=> usr_data.b);