the different between join condition and where condition
Somebody tell me what's the difference between two queries:
Version A
select开发者_运维技巧 p.LastName, o.OrderNo
from Persons p, Orders o
where p.P_Id = o.P_Id
...and...
Version B
select p.LastName, o.OrderNo
from Persons p
join Orders o on p.P_Id = o.P_Id
Both use an INNER JOIN to combine records between the PERSONS and ORDERS tables. Version A is ANSI-89 syntax, and Version B is ANSI-92 syntax.
There's no performance difference between them, but the ANSI-92 syntax supports OUTER JOINs (LEFT, RIGHT, and FULL depending on the database) while the ANSI-89 does not.
assuming that "join" is a shorthand syntax for "inner join" i see no difference.
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