Consider
SQL> select deptno from emp,
dept;
select deptno from emp, dept * ERROR at line 1: ORA-00918: column ambiguously defined The
column deptno would be checked against one of the tables and would be found
to
be
valid, but the checking cannot stop there. The other table must also be checked
for
a
possible conflict ( which there is in this case ).
select
d.deptno from emp e, dept d;
Does
not just resolve the conflict, it removes the need for any checking on
emp.
Any
column which is not aliased will have to be checked against ALL tables
mentioned,
so
aliasing can save quite a lot of time.
Regards
Garry
-----Original
Message----- From: novicedba [mailto:[EMAIL PROTECTED]] Sent: 10 July 2001 12:11
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- table aliases save time when parsing?? novicedba
- Re: table aliases save time when parsing?? Igor Neyman
- Re[2]: table aliases save time when parsing?? dgoulet
- Gillies, Garry