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@ -1,5 +1,5 @@ |
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<!-- |
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$Header: /cvsroot/pgsql/doc/src/sgml/Attic/inherit.sgml,v 1.18 2002/01/07 02:29:12 petere Exp $ |
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$Header: /cvsroot/pgsql/doc/src/sgml/Attic/inherit.sgml,v 1.19 2002/04/13 17:17:29 tgl Exp $ |
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--> |
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<chapter id="inherit"> |
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@ -56,35 +56,28 @@ SELECT name, altitude |
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which returns: |
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<programlisting> |
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+----------+----------+ |
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|name | altitude | |
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+----------+----------+ |
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|Las Vegas | 2174 | |
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+----------+----------+ |
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|Mariposa | 1953 | |
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+----------+----------+ |
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|Madison | 845 | |
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+----------+----------+ |
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name | altitude |
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-----------+---------- |
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Las Vegas | 2174 |
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Mariposa | 1953 |
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Madison | 845 |
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</programlisting> |
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</para> |
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<para> |
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On the other hand, the following query finds |
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all the cities that are not state capitals and |
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are situated at an altitude of 500ft or higher: |
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are situated at an altitude over 500ft: |
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<programlisting> |
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SELECT name, altitude |
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FROM ONLY cities |
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WHERE altitude > 500; |
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+----------+----------+ |
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|name | altitude | |
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+----------+----------+ |
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|Las Vegas | 2174 | |
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+----------+----------+ |
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|Mariposa | 1953 | |
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+----------+----------+ |
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name | altitude |
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-----------+---------- |
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Las Vegas | 2174 |
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Mariposa | 1953 |
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</programlisting> |
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</para> |
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@ -112,18 +105,16 @@ SELECT name, altitude |
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which returns: |
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<programlisting> |
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+---------+----------+----------+ |
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|tableoid |name | altitude | |
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+---------+----------+----------+ |
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|37292 |Las Vegas | 2174 | |
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+---------+----------+----------+ |
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|37280 |Mariposa | 1953 | |
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+---------+----------+----------+ |
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|37280 |Madison | 845 | |
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+---------+----------+----------+ |
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tableoid | name | altitude |
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----------+-----------+---------- |
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139793 | Las Vegas | 2174 |
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139793 | Mariposa | 1953 |
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139798 | Madison | 845 |
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</programlisting> |
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If you do a join with pg_class you can see the actual table name: |
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(If you try to reproduce this example, you will probably get different |
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numeric OIDs.) By doing a join with pg_class you can see the actual table |
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names: |
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<programlisting> |
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SELECT p.relname, c.name, c.altitude |
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@ -134,15 +125,11 @@ SELECT name, altitude |
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which returns: |
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<programlisting> |
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+---------+----------+----------+ |
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|relname |name | altitude | |
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+---------+----------+----------+ |
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|capitals |Las Vegas | 2174 | |
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+---------+----------+----------+ |
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|cities |Mariposa | 1953 | |
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+---------+----------+----------+ |
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|cities |Madison | 845 | |
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+---------+----------+----------+ |
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relname | name | altitude |
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----------+-----------+---------- |
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cities | Las Vegas | 2174 |
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cities | Mariposa | 1953 |
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capitals | Madison | 845 |
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</programlisting> |
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</para> |
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