Vlastnosti spojení (join)
Pokud v návrhu dotazu poklepete na spojnici mezi dvěma poli nebo zvolíte Vložit - Nová relace, zobrazí se dialog Vlastnosti spojení. Možnosti, které nastavíte, se použijí pro všechny nově vytvořené dotazy.
Použité tabulky
Určuje dvě různé tabulky, které si přejete propojit.
Použitá pole
Určuje dvě pole, která budou spojena relací.
Možnosti
Typ
Specifies the join type of the selected join. Some databases support only a subset of the various possible types.
Vnitřní spoj
In an inner join, the results table contains only those records for which the content of the linked fields is the same. In LibreOfficeDev SQL this type of link is created by a corresponding WHERE clause.
Levý spoj
In a left join, the results table contains all records of the queried fields from the left table and only those records of the queried fields from the right table for which the content of the linked fields is the same. In LibreOfficeDev SQL this type of link corresponds to the LEFT OUTER JOIN command.
Pravý spoj
In a right join, the results table contains all records of the queried fields from the right table and only those records of the queried fields from the left table for which the content of the linked fields is the same. In LibreOfficeDev SQL this type of link corresponds to the RIGHT OUTER JOIN command.
Plný spoj
In a full join, the results table contains all records of the queried fields from the left and right tables. In the SQL of LibreOfficeDev this type of link corresponds to the FULL OUTER JOIN command.
Přirozené
In a natural join, the keyword NATURAL in inserted into the SQL statement that defines the relation. The relation joins all columns that have the same column name in both tables. The resulting joined table contains only one column for each pair of equally named columns.