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-rw-r--r--doc/src/sgml/queries.sgml84
1 files changed, 83 insertions, 1 deletions
diff --git a/doc/src/sgml/queries.sgml b/doc/src/sgml/queries.sgml
index 28aeccf96f9..7f16eb7af9d 100644
--- a/doc/src/sgml/queries.sgml
+++ b/doc/src/sgml/queries.sgml
@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/queries.sgml,v 1.6 2001/03/24 23:03:26 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/queries.sgml,v 1.7 2001/05/12 22:51:35 petere Exp $ -->
<chapter id="queries">
<title>Queries</title>
@@ -102,6 +102,10 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<sect3 id="queries-join">
<title>Joined Tables</title>
+ <indexterm zone="queries-join">
+ <primary>joins</primary>
+ </indexterm>
+
<para>
A joined table is a table derived from two other (real or
derived) tables according to the rules of the particular join
@@ -115,6 +119,10 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<term>CROSS JOIN</term>
<listitem>
+ <indexterm>
+ <primary>joins</primary>
+ <secondary>cross</secondary>
+ </indexterm>
<synopsis>
<replaceable>T1</replaceable> CROSS JOIN <replaceable>T2</replaceable>
</synopsis>
@@ -145,6 +153,11 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<term>Qualified JOINs</term>
<listitem>
+ <indexterm>
+ <primary>joins</primary>
+ <secondary>outer</secondary>
+ </indexterm>
+
<synopsis>
<replaceable>T1</replaceable> { <optional>INNER</optional> | { LEFT | RIGHT | FULL } <optional>OUTER</optional> } JOIN <replaceable>T2</replaceable> ON <replaceable>boolean_expression</replaceable>
<replaceable>T1</replaceable> { <optional>INNER</optional> | { LEFT | RIGHT | FULL } <optional>OUTER</optional> } JOIN <replaceable>T2</replaceable> USING ( <replaceable>join column list</replaceable> )
@@ -187,6 +200,10 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
</para>
<para>
+ <indexterm>
+ <primary>joins</primary>
+ <secondary>natural</secondary>
+ </indexterm>
Finally, NATURAL is a shorthand form of USING: it forms a USING
list consisting of exactly those column names that appear in both
input tables. As with USING, these columns appear only once in
@@ -213,6 +230,11 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<term>LEFT OUTER JOIN</term>
<listitem>
+ <indexterm>
+ <primary>joins</primary>
+ <secondary>left</secondary>
+ </indexterm>
+
<para>
First, an INNER JOIN is performed. Then, for each row in T1
that does not satisfy the join condition with any row in
@@ -268,6 +290,10 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<sect3 id="queries-subqueries">
<title>Subqueries</title>
+ <indexterm zone="queries-subqueries">
+ <primary>subqueries</primary>
+ </indexterm>
+
<para>
Subqueries specifying a derived table must be enclosed in
parentheses and <emphasis>must</emphasis> be named using an AS
@@ -289,6 +315,16 @@ FROM (SELECT * FROM table1) AS alias_name
<sect3 id="queries-table-aliases">
<title>Table and Column Aliases</title>
+ <indexterm zone="queries-table-aliases">
+ <primary>label</primary>
+ <secondary>table</secondary>
+ </indexterm>
+
+ <indexterm>
+ <primary>alias</primary>
+ <see>label</see>
+ </indexterm>
+
<para>
A temporary name can be given to tables and complex table
references to be used for references to the derived table in
@@ -400,6 +436,10 @@ FROM (SELECT * FROM T1) DT1, T2, T3
<sect2 id="queries-where">
<title>WHERE clause</title>
+ <indexterm zone="queries-where">
+ <primary>where</primary>
+ </indexterm>
+
<para>
The syntax of the WHERE clause is
<synopsis>
@@ -482,6 +522,10 @@ FROM FDT WHERE
<sect2 id="queries-group">
<title>GROUP BY and HAVING clauses</title>
+ <indexterm zone="queries-group">
+ <primary>group</primary>
+ </indexterm>
+
<para>
After passing the WHERE filter, the derived input table may be
subject to grouping, using the GROUP BY clause, and elimination of
@@ -578,6 +622,11 @@ SELECT pid AS "Products",
<sect1 id="queries-select-lists">
<title>Select Lists</title>
+ <indexterm>
+ <primary>select</primary>
+ <secondary>select list</secondary>
+ </indexterm>
+
<para>
As shown in the previous section,
the table expression in the <command>SELECT</command> command
@@ -620,6 +669,11 @@ SELECT tbl1.a, tbl2.b, tbl1.c FROM ...
<sect2 id="queries-column-labels">
<title>Column Labels</title>
+ <indexterm zone="queries-column-labels">
+ <primary>label</primary>
+ <secondary>column</secondary>
+ </indexterm>
+
<para>
The entries in the select list can be assigned names for further
processing. The <quote>further processing</quote> in this case is
@@ -652,6 +706,10 @@ SELECT a AS value, b + c AS sum FROM ...
<sect2 id="queries-distinct">
<title>DISTINCT</title>
+ <indexterm zone="queries-distinct">
+ <primary>distinct</primary>
+ </indexterm>
+
<para>
After the select list has been processed, the result table may
optionally be subject to the elimination of duplicates. The
@@ -700,6 +758,16 @@ SELECT DISTINCT ON (<replaceable>expression</replaceable> <optional>, <replaceab
<sect1 id="queries-union">
<title>Combining Queries</title>
+ <indexterm zone="queries-union">
+ <primary>union</primary>
+ </indexterm>
+ <indexterm zone="queries-union">
+ <primary>intersection</primary>
+ </indexterm>
+ <indexterm zone="queries-union">
+ <primary>except</primary>
+ </indexterm>
+
<para>
The results of two queries can be combined using the set operations
union, intersection, and difference. The syntax is
@@ -756,6 +824,11 @@ SELECT DISTINCT ON (<replaceable>expression</replaceable> <optional>, <replaceab
<sect1 id="queries-order">
<title>Sorting Rows</title>
+
+ <indexterm zone="queries-order">
+ <primary>sorting</primary>
+ <secondary>query results</secondary>
+ </indexterm>
<para>
After a query has produced an output table (after the select list
@@ -817,6 +890,15 @@ SELECT a AS b FROM table1 ORDER BY a;
<sect1 id="queries-limit">
<title>LIMIT and OFFSET</title>
+ <indexterm zone="queries-limit">
+ <primary>limit</primary>
+ </indexterm>
+
+ <indexterm zone="queries-limit">
+ <primary>offset</primary>
+ <secondary>with query results</secondary>
+ </indexterm>
+
<synopsis>
SELECT <replaceable>select_list</replaceable> FROM <replaceable>table_expression</replaceable> <optional>ORDER BY <replaceable>sort_spec</replaceable></optional> <optional>LIMIT { <replaceable>number</replaceable> | ALL }</optional> <optional>OFFSET <replaceable>number</replaceable></optional>
</synopsis>
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