diff options
| -rw-r--r-- | doc/src/sgml/query.sgml | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/doc/src/sgml/query.sgml b/doc/src/sgml/query.sgml index c0889743c4c..bdb455f3008 100644 --- a/doc/src/sgml/query.sgml +++ b/doc/src/sgml/query.sgml @@ -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 < W2.temp_lo AND W1.temp_hi > 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 |