Vnořené SQL dotazy ?

1. Návštěvník 4BF3B505 3. 1. 2004 03:03

   Zdravim, netušíte jestli MySQL, které tu běží podporuje vnořené dotazy? Nefunguje mi dotaz: SELECT cislo FROM Cela WHERE cislo NOT IN (SELECT Uvez1_cislo FROM Vysetrovany); ma to umet vybrat cisla cel, ktera nema uveden zadny vysetrovany v jine tabulce... Diky.

2. Návštěvník 4BF3B505 3. 1. 2004 03:36

   Odpovím si sám, chytrý manual řekl: For MySQL versions prior to 4.1, most subqueries can be successfully rewritten using joins and and other methods. See section 6.4.2.11 Rewriting Subqueries for Earlier MySQL Versions. --> It is often possible to rewrite a query without a subquery: SELECT * FROM t1 WHERE id IN (SELECT id FROM t2); This can be rewritten as: SELECT t1.* FROM t1,t2 WHERE t1.id=t2.id; The queries: SELECT * FROM t1 WHERE id NOT IN (SELECT id FROM t2); SELECT * FROM t1 WHERE NOT EXISTS (SELECT id FROM t2 WHERE t1.id=t2.id); Can be rewritten as: SELECT table1.* FROM table1 LEFT JOIN table2 ON table1.id=table2.id WHERE table2.id IS NULL; --------------- Takze dotaz zhora mi facha v tyhle podobe: SELECT cislo FROM Cela c LEFT JOIN Vysetrovany v ON c.cislo = v.uvez1_cislo WHERE v.uvez1_cislo IS NULL je to divny, co...

3. Návštěvník B96BB00D 14. 1. 2004 01:44

   nebolo by jednoduchsie upgrade na MySQL ver 4.1 ? lebo ja by som tiez potreboval vnorene selecty pouzit :(((

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