diff options
Diffstat (limited to 'doc/src/sgml/ref/select.sgml')
| -rw-r--r-- | doc/src/sgml/ref/select.sgml | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml index 7192de53e0d..cad427da3c6 100644 --- a/doc/src/sgml/ref/select.sgml +++ b/doc/src/sgml/ref/select.sgml @@ -1,5 +1,5 @@ <!-- -$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.60 2002/08/30 16:00:41 momjian Exp $ +$Header: /cvsroot/pgsql/doc/src/sgml/ref/select.sgml,v 1.61 2002/09/21 18:32:54 petere Exp $ PostgreSQL documentation --> @@ -451,8 +451,8 @@ where <replaceable class="PARAMETER">from_item</replaceable> can be: (i.e., all combined rows that pass its ON condition), plus one copy of each row in the left-hand table for which there was no right-hand row that passed the ON condition. This left-hand row is extended to the full - width of the joined table by inserting NULLs for the right-hand columns. - Note that only the JOIN's own ON or USING condition is considered while + width of the joined table by inserting null values for the right-hand columns. + Note that only the <literal>JOIN</>'s own ON or USING condition is considered while deciding which rows have matches. Outer ON or WHERE conditions are applied afterwards. </para> @@ -647,11 +647,13 @@ SELECT name FROM distributors ORDER BY code; </para> <para> - Optionally one may add the keyword DESC (descending) - or ASC (ascending) after each column name in the ORDER BY clause. - If not specified, ASC is assumed by default. Alternatively, a - specific ordering operator name may be specified. ASC is equivalent - to USING < and DESC is equivalent to USING >. + Optionally one may add the key word <literal>DESC</> (descending) + or <literal>ASC</> (ascending) after each column name in the + <literal>ORDER BY</> clause. If not specified, <literal>ASC</> is + assumed by default. Alternatively, a specific ordering operator + name may be specified. <literal>ASC</> is equivalent to + <literal>USING <</> and <literal>DESC</> is equivalent to + <literal>USING ></>. </para> <para> @@ -689,7 +691,7 @@ SELECT name FROM distributors ORDER BY code; <para> The UNION operator computes the collection (set union) of the rows returned by the queries involved. - The two SELECTs that represent the direct operands of the UNION must + The two SELECT statements that represent the direct operands of the UNION must produce the same number of columns, and corresponding columns must be of compatible data types. </para> @@ -1064,7 +1066,7 @@ SELECT * FROM distributors_2(111) AS (f1 int, f2 text); <para> <productname>PostgreSQL</productname> allows one to omit the <command>FROM</command> clause from a query. This feature -was retained from the original PostQuel query language. It has +was retained from the original PostQUEL query language. It has a straightforward use to compute the results of simple expressions: <programlisting> @@ -1075,7 +1077,7 @@ SELECT 2+2; 4 </programlisting> -Some other DBMSes cannot do this except by introducing a dummy one-row +Some other SQL databases cannot do this except by introducing a dummy one-row table to do the select from. A less obvious use is to abbreviate a normal select from one or more tables: |