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Add more appropriate markup.

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This commit is contained in:
Peter Eisentraut
2002-09-21 18:32:54 +00:00
parent 7233aae50b
commit bc49968764
77 changed files with 1481 additions and 1347 deletions
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24
doc/src/sgml/syntax.sgml
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@@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.69 2002/09/12 22:05:36 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/syntax.sgml,v 1.70 2002/09/21 18:32:54 petere Exp $
-->
<chapter id="sql-syntax">
@@ -715,19 +715,19 @@ SELECT (5 !) - 6;
<row>
<entry><token>IS</token></entry>
<entry></entry>
<entry>test for TRUE, FALSE, UNKNOWN, NULL</entry>
<entry><literal>IS TRUE</>, <literal>IS FALSE</>, <literal>IS UNKNOWN</>, <literal>IS NULL</></entry>
</row>
<row>
<entry><token>ISNULL</token></entry>
<entry></entry>
<entry>test for NULL</entry>
<entry>test for null</entry>
</row>
<row>
<entry><token>NOTNULL</token></entry>
<entry></entry>
<entry>test for NOT NULL</entry>
<entry>test for not null</entry>
</row>
<row>
@@ -1042,13 +1042,13 @@ sqrt(2)
<para>
The first form of aggregate expression invokes the aggregate
across all input rows for which the given expression yields a
non-NULL value. (Actually, it is up to the aggregate function
whether to ignore NULLs or not --- but all the standard ones do.)
non-null value. (Actually, it is up to the aggregate function
whether to ignore null values or not --- but all the standard ones do.)
The second form is the same as the first, since
<literal>ALL</literal> is the default. The third form invokes the
aggregate for all distinct non-NULL values of the expression found
aggregate for all distinct non-null values of the expression found
in the input rows. The last form invokes the aggregate once for
each input row regardless of NULL or non-NULL values; since no
each input row regardless of null or non-null values; since no
particular input value is specified, it is generally only useful
for the <function>count()</function> aggregate function.
</para>
@@ -1056,9 +1056,9 @@ sqrt(2)
<para>
For example, <literal>count(*)</literal> yields the total number
of input rows; <literal>count(f1)</literal> yields the number of
input rows in which <literal>f1</literal> is non-NULL;
input rows in which <literal>f1</literal> is non-null;
<literal>count(distinct f1)</literal> yields the number of
distinct non-NULL values of <literal>f1</literal>.
distinct non-null values of <literal>f1</literal>.
</para>
<para>
@@ -1106,7 +1106,7 @@ CAST ( <replaceable>expression</replaceable> AS <replaceable>type</replaceable>
to the type that a value expression must produce (for example, when it is
assigned to a table column); the system will automatically apply a
type cast in such cases. However, automatic casting is only done for
cast functions that are marked <quote>okay to apply implicitly</>
cast functions that are marked <quote>OK to apply implicitly</>
in the system catalogs. Other cast functions must be invoked with
explicit casting syntax. This restriction is intended to prevent
surprising conversions from being applied silently.
@@ -1140,7 +1140,7 @@ CAST ( <replaceable>expression</replaceable> AS <replaceable>type</replaceable>
It is an error to use a query that
returns more than one row or more than one column as a scalar subquery.
(But if, during a particular execution, the subquery returns no rows,
there is no error; the scalar result is taken to be NULL.)
there is no error; the scalar result is taken to be null.)
The subquery can refer to variables from the surrounding query,
which will act as constants during any one evaluation of the subquery.
See also <xref linkend="functions-subquery">.