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doc: Use tags consistently in the tutorial chapter

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Make more consistent use of <screen> and <programlisting>.

Author: Jürgen Purtz <juergen@purtz.de>
Discussion: https://www.postgresql.org/message-id/flat/158996922318.7035.10603922579567326239@wrigleys.postgresql.org
This commit is contained in:
Peter Eisentraut 2020-09-04 08:19:20 +02:00
parent 96cfcadd26
commit 6eee73e4e5
1 changed files with 6 additions and 2 deletions
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8
doc/src/sgml/query.sgml
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@ -564,14 +564,16 @@ SELECT *
<programlisting>
SELECT *
FROM weather LEFT OUTER JOIN cities ON (weather.city = cities.name);
</programlisting>
<screen>
city | temp_lo | temp_hi | prcp | date | name | location
---------------+---------+---------+------+------------+---------------+-----------
Hayward | 37 | 54 | | 1994-11-29 | |
San Francisco | 46 | 50 | 0.25 | 1994-11-27 | San Francisco | (-194,53)
San Francisco | 43 | 57 | 0 | 1994-11-29 | San Francisco | (-194,53)
(3 rows)
</programlisting>
</screen>
This query is called a <firstterm>left outer
join</firstterm> because the table mentioned on the left of the
@ -612,13 +614,15 @@ SELECT W1.city, W1.temp_lo AS low, W1.temp_hi AS high,
FROM weather W1, weather W2
WHERE W1.temp_lo &lt; W2.temp_lo
AND W1.temp_hi &gt; W2.temp_hi;
</programlisting>
<screen>
city | low | high | city | low | high
---------------+-----+------+---------------+-----+------
San Francisco | 43 | 57 | San Francisco | 46 | 50
Hayward | 37 | 54 | San Francisco | 46 | 50
(2 rows)
</programlisting>
</screen>
Here we have relabeled the weather table as <literal>W1</literal> and
<literal>W2</literal> to be able to distinguish the left and right side