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-rw-r--r--doc/src/sgml/queries.sgml125
1 files changed, 101 insertions, 24 deletions
diff --git a/doc/src/sgml/queries.sgml b/doc/src/sgml/queries.sgml
index d3ec786ac27..b717ad445a0 100644
--- a/doc/src/sgml/queries.sgml
+++ b/doc/src/sgml/queries.sgml
@@ -1,8 +1,16 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/queries.sgml,v 1.22 2003/08/14 23:13:27 tgl Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/queries.sgml,v 1.23 2003/08/31 17:32:19 petere Exp $ -->
<chapter id="queries">
<title>Queries</title>
+ <indexterm zone="queries">
+ <primary>query</primary>
+ </indexterm>
+
+ <indexterm zone="queries">
+ <primary>SELECT</primary>
+ </indexterm>
+
<para>
The previous chapters explained how to create tables, how to fill
them with data, and how to manipulate that data. Now we finally
@@ -73,6 +81,10 @@ SELECT random();
<sect1 id="queries-table-expressions">
<title>Table Expressions</title>
+ <indexterm zone="queries-table-expressions">
+ <primary>table expression</primary>
+ </indexterm>
+
<para>
A <firstterm>table expression</firstterm> computes a table. The
table expression contains a <literal>FROM</> clause that is
@@ -112,6 +124,10 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
overall table expression.
</para>
+ <indexterm>
+ <primary>ONLY</primary>
+ </indexterm>
+
<para>
When a table reference names a table that is the supertable of a
table inheritance hierarchy, the table reference produces rows of
@@ -125,7 +141,7 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<title>Joined Tables</title>
<indexterm zone="queries-join">
- <primary>joins</primary>
+ <primary>join</primary>
</indexterm>
<para>
@@ -141,10 +157,14 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<term>Cross join</term>
<indexterm>
- <primary>joins</primary>
+ <primary>join</primary>
<secondary>cross</secondary>
</indexterm>
+ <indexterm>
+ <primary>cross join</primary>
+ </indexterm>
+
<listitem>
<synopsis>
<replaceable>T1</replaceable> CROSS JOIN <replaceable>T2</replaceable>
@@ -175,10 +195,14 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<term>Qualified joins</term>
<indexterm>
- <primary>joins</primary>
+ <primary>join</primary>
<secondary>outer</secondary>
</indexterm>
+ <indexterm>
+ <primary>outer join</primary>
+ </indexterm>
+
<listitem>
<synopsis>
<replaceable>T1</replaceable> { <optional>INNER</optional> | { LEFT | RIGHT | FULL } <optional>OUTER</optional> } JOIN <replaceable>T2</replaceable> ON <replaceable>boolean_expression</replaceable>
@@ -227,9 +251,12 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<para>
<indexterm>
- <primary>joins</primary>
+ <primary>join</primary>
<secondary>natural</secondary>
</indexterm>
+ <indexterm>
+ <primary>natural join</primary>
+ </indexterm>
Finally, <literal>NATURAL</> is a shorthand form of
<literal>USING</>: it forms a <literal>USING</> list
consisting of exactly those column names that appear in both
@@ -256,10 +283,14 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<term><literal>LEFT OUTER JOIN</></term>
<indexterm>
- <primary>joins</primary>
+ <primary>join</primary>
<secondary>left</secondary>
</indexterm>
+ <indexterm>
+ <primary>left join</primary>
+ </indexterm>
+
<listitem>
<para>
First, an inner join is performed. Then, for each row in
@@ -274,6 +305,15 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<varlistentry>
<term><literal>RIGHT OUTER JOIN</></term>
+ <indexterm>
+ <primary>join</primary>
+ <secondary>right</secondary>
+ </indexterm>
+
+ <indexterm>
+ <primary>right join</primary>
+ </indexterm>
+
<listitem>
<para>
First, an inner join is performed. Then, for each row in
@@ -424,13 +464,13 @@ FROM <replaceable>table_reference</replaceable> <optional>, <replaceable>table_r
<title>Table and Column Aliases</title>
<indexterm zone="queries-table-aliases">
- <primary>label</primary>
- <secondary>table</secondary>
+ <primary>alias</primary>
+ <secondary>in the FROM clause</secondary>
</indexterm>
<indexterm>
- <primary>alias</primary>
- <see>label</see>
+ <primary>label</primary>
+ <see>alias</see>
</indexterm>
<para>
@@ -530,7 +570,7 @@ SELECT a.* FROM (my_table AS a JOIN your_table AS b ON ...) AS c
<title>Subqueries</title>
<indexterm zone="queries-subqueries">
- <primary>subqueries</primary>
+ <primary>subquery</primary>
</indexterm>
<para>
@@ -556,6 +596,11 @@ FROM (SELECT * FROM table1) AS alias_name
<indexterm zone="queries-tablefunctions"><primary>table function</></>
+ <indexterm zone="queries-tablefunctions">
+ <primary>function</>
+ <secondary>in the FROM clause</>
+ </indexterm>
+
<para>
Table functions are functions that produce a set of rows, made up
of either base data types (scalar types) or composite data types
@@ -628,7 +673,7 @@ SELECT *
<title>The WHERE Clause</title>
<indexterm zone="queries-where">
- <primary>where</primary>
+ <primary>WHERE</primary>
</indexterm>
<para>
@@ -716,7 +761,11 @@ SELECT ... FROM fdt WHERE EXISTS (SELECT c1 FROM t2 WHERE c2 > fdt.c1)
<title>The GROUP BY and HAVING Clauses</title>
<indexterm zone="queries-group">
- <primary>group</primary>
+ <primary>GROUP BY</primary>
+ </indexterm>
+
+ <indexterm zone="queries-group">
+ <primary>grouping</primary>
</indexterm>
<para>
@@ -827,6 +876,10 @@ SELECT product_id, p.name, (sum(s.units) * p.price) AS sales
column names is also allowed.
</para>
+ <indexterm>
+ <primary>HAVING</primary>
+ </indexterm>
+
<para>
If a table has been grouped using a <literal>GROUP BY</literal>
clause, but then only certain groups are of interest, the
@@ -884,7 +937,7 @@ SELECT product_id, p.name, (sum(s.units) * (p.price - p.cost)) AS profit
<title>Select Lists</title>
<indexterm>
- <primary>select</primary>
+ <primary>SELECT</primary>
<secondary>select list</secondary>
</indexterm>
@@ -901,6 +954,10 @@ SELECT product_id, p.name, (sum(s.units) * (p.price - p.cost)) AS profit
<sect2 id="queries-select-list-items">
<title>Select-List Items</title>
+ <indexterm>
+ <primary>*</primary>
+ </indexterm>
+
<para>
The simplest kind of select list is <literal>*</literal> which
emits all columns that the table expression produces. Otherwise,
@@ -944,8 +1001,8 @@ SELECT tbl1.a, tbl2.a, tbl1.b FROM ...
<title>Column Labels</title>
<indexterm zone="queries-column-labels">
- <primary>label</primary>
- <secondary>column</secondary>
+ <primary>alias</primary>
+ <secondary>in the select list</secondary>
</indexterm>
<para>
@@ -981,7 +1038,11 @@ SELECT a AS value, b + c AS sum FROM ...
<title>DISTINCT</title>
<indexterm zone="queries-distinct">
- <primary>distinct</primary>
+ <primary>DISTINCT</primary>
+ </indexterm>
+
+ <indexterm zone="queries-distinct">
+ <primary>duplicates</primary>
</indexterm>
<para>
@@ -997,6 +1058,8 @@ SELECT DISTINCT <replaceable>select_list</replaceable> ...
</para>
<para>
+ <indexterm><primary>null value</><secondary sortas="DISTINCT">in
+ DISTINCT</></indexterm>
Obviously, two rows are considered distinct if they differ in at
least one column value. Null values are considered equal in this
comparison.
@@ -1035,13 +1098,25 @@ SELECT DISTINCT ON (<replaceable>expression</replaceable> <optional>, <replaceab
<title>Combining Queries</title>
<indexterm zone="queries-union">
- <primary>union</primary>
+ <primary>UNION</primary>
+ </indexterm>
+ <indexterm zone="queries-union">
+ <primary>INTERSECT</primary>
+ </indexterm>
+ <indexterm zone="queries-union">
+ <primary>EXCEPT</primary>
+ </indexterm>
+ <indexterm zone="queries-union">
+ <primary>set union</primary>
+ </indexterm>
+ <indexterm zone="queries-union">
+ <primary>set intersection</primary>
</indexterm>
<indexterm zone="queries-union">
- <primary>intersection</primary>
+ <primary>set difference</primary>
</indexterm>
<indexterm zone="queries-union">
- <primary>except</primary>
+ <primary>set operation</primary>
</indexterm>
<para>
@@ -1104,7 +1179,10 @@ SELECT DISTINCT ON (<replaceable>expression</replaceable> <optional>, <replaceab
<indexterm zone="queries-order">
<primary>sorting</primary>
- <secondary>query results</secondary>
+ </indexterm>
+
+ <indexterm zone="queries-order">
+ <primary>ORDER BY</primary>
</indexterm>
<para>
@@ -1173,12 +1251,11 @@ SELECT a AS b FROM table1 ORDER BY a;
<title>LIMIT and OFFSET</title>
<indexterm zone="queries-limit">
- <primary>limit</primary>
+ <primary>LIMIT</primary>
</indexterm>
<indexterm zone="queries-limit">
- <primary>offset</primary>
- <secondary>with query results</secondary>
+ <primary>OFFSET</primary>
</indexterm>
<para>
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-16 16:47:28 +0000