database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-10-27 00:12:01 +03:00
Code Activity

Don't use SGML empty tags

Browse Source 
For DocBook XML compatibility, don't use SGML empty tags (</>) anymore,
replace by the full tag name.  Add a warning option to catch future
occurrences.

Alexander Lakhin, Jürgen Purtz
This commit is contained in:
Peter Eisentraut
2017-10-08 21:44:17 -04:00
parent 6ecabead4b
commit c29c578908
337 changed files with 31636 additions and 31635 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
doc/src/sgml/query.sgml
View File

@@ -29,7 +29,7 @@
in the directory <filename>src/tutorial/</filename>. (Binary
distributions of <productname>PostgreSQL</productname> might not
compile these files.) To use those
files, first change to that directory and run <application>make</>:
files, first change to that directory and run <application>make</application>:
<screen>
<prompt>$</prompt> <userinput>cd <replaceable>....</replaceable>/src/tutorial</userinput>
@@ -50,7 +50,7 @@
</screen>
The <literal>\i</literal> command reads in commands from the
specified file. <command>psql</command>'s <literal>-s</> option puts you in
specified file. <command>psql</command>'s <literal>-s</literal> option puts you in
single step mode which pauses before sending each statement to the
server. The commands used in this section are in the file
<filename>basics.sql</filename>.
@@ -155,8 +155,8 @@ CREATE TABLE weather (
<productname>PostgreSQL</productname> supports the standard
<acronym>SQL</acronym> types <type>int</type>,
<type>smallint</type>, <type>real</type>, <type>double
precision</type>, <type>char(<replaceable>N</>)</type>,
<type>varchar(<replaceable>N</>)</type>, <type>date</type>,
precision</type>, <type>char(<replaceable>N</replaceable>)</type>,
<type>varchar(<replaceable>N</replaceable>)</type>, <type>date</type>,
<type>time</type>, <type>timestamp</type>, and
<type>interval</type>, as well as other types of general utility
and a rich set of geometric types.
@@ -211,7 +211,7 @@ INSERT INTO weather VALUES ('San Francisco', 46, 50, 0.25, '1994-11-27');
Note that all data types use rather obvious input formats.
Constants that are not simple numeric values usually must be
surrounded by single quotes (<literal>'</>), as in the example.
surrounded by single quotes (<literal>'</literal>), as in the example.
The
<type>date</type> type is actually quite flexible in what it
accepts, but for this tutorial we will stick to the unambiguous
@@ -336,8 +336,8 @@ SELECT city, (temp_hi+temp_lo)/2 AS temp_avg, date FROM weather;
</para>
<para>
A query can be <quote>qualified</> by adding a <literal>WHERE</>
clause that specifies which rows are wanted. The <literal>WHERE</>
A query can be <quote>qualified</quote> by adding a <literal>WHERE</literal>
clause that specifies which rows are wanted. The <literal>WHERE</literal>
clause contains a Boolean (truth value) expression, and only rows for
which the Boolean expression is true are returned. The usual
Boolean operators (<literal>AND</literal>,
@@ -446,9 +446,9 @@ SELECT DISTINCT city
of the same or different tables at one time is called a
<firstterm>join</firstterm> query. As an example, say you wish to
list all the weather records together with the location of the
associated city. To do that, we need to compare the <structfield>city</>
column of each row of the <structname>weather</> table with the
<structfield>name</> column of all rows in the <structname>cities</>
associated city. To do that, we need to compare the <structfield>city</structfield>
column of each row of the <structname>weather</structname> table with the
<structfield>name</structfield> column of all rows in the <structname>cities</structname>
table, and select the pairs of rows where these values match.
<note>
<para>
@@ -483,7 +483,7 @@ SELECT *
There is no result row for the city of Hayward. This is
because there is no matching entry in the
<structname>cities</structname> table for Hayward, so the join
ignores the unmatched rows in the <structname>weather</> table. We will see
ignores the unmatched rows in the <structname>weather</structname> table. We will see
shortly how this can be fixed.
</para>
</listitem>
@@ -520,7 +520,7 @@ SELECT city, temp_lo, temp_hi, prcp, date, location
Since the columns all had different names, the parser
automatically found which table they belong to. If there
were duplicate column names in the two tables you'd need to
<firstterm>qualify</> the column names to show which one you
<firstterm>qualify</firstterm> the column names to show which one you
meant, as in:
<programlisting>
@@ -599,7 +599,7 @@ SELECT *
<firstterm>self join</firstterm>. As an example, suppose we wish
to find all the weather records that are in the temperature range
of other weather records. So we need to compare the
<structfield>temp_lo</> and <structfield>temp_hi</> columns of
<structfield>temp_lo</structfield> and <structfield>temp_hi</structfield> columns of
each <structname>weather</structname> row to the
<structfield>temp_lo</structfield> and
<structfield>temp_hi</structfield> columns of all other
@@ -620,8 +620,8 @@ SELECT W1.city, W1.temp_lo AS low, W1.temp_hi AS high,
(2 rows)
</programlisting>
Here we have relabeled the weather table as <literal>W1</> and
<literal>W2</> to be able to distinguish the left and right side
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
of the join. You can also use these kinds of aliases in other
queries to save some typing, e.g.:
<programlisting>
@@ -644,7 +644,7 @@ SELECT *
<para>
Like most other relational database products,
<productname>PostgreSQL</productname> supports
<firstterm>aggregate functions</>.
<firstterm>aggregate functions</firstterm>.
An aggregate function computes a single result from multiple input rows.
For example, there are aggregates to compute the
<function>count</function>, <function>sum</function>,
@@ -747,7 +747,7 @@ SELECT city, max(temp_lo)
</screen>
which gives us the same results for only the cities that have all
<structfield>temp_lo</> values below 40. Finally, if we only care about
<structfield>temp_lo</structfield> values below 40. Finally, if we only care about
cities whose
names begin with <quote><literal>S</literal></quote>, we might do:
@@ -871,7 +871,7 @@ DELETE FROM <replaceable>tablename</replaceable>;
</synopsis>
Without a qualification, <command>DELETE</command> will
remove <emphasis>all</> rows from the given table, leaving it
remove <emphasis>all</emphasis> rows from the given table, leaving it
empty. The system will not request confirmation before
doing this!
</para>