-<REFENTRY ID="SQL-SELECT-1">
-<REFMETA>
-<REFENTRYTITLE>
-SELECT
-</REFENTRYTITLE>
-<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
-</REFMETA>
-<REFNAMEDIV>
-<REFNAME>
-SELECT
-</REFNAME>
-<REFPURPOSE>
-Retrieve rows from a table or view
-</REFPURPOSE>
-<REFSYNOPSISDIV>
-<REFSYNOPSISDIVINFO>
-<DATE>1998-04-15</DATE>
-</REFSYNOPSISDIVINFO>
-<SYNOPSIS>
-<REPLACEABLE CLASS="PARAMETER">
-</REPLACEABLE>
+<refentry id="SQL-SELECT">
+ <refmeta>
+ <refentrytitle>
+ SELECT
+ </refentrytitle>
+ <refmiscinfo>SQL - Language Statements</refmiscinfo>
+ </refmeta>
+ <refnamediv>
+ <refname>
+ SELECT
+ </refname>
+ <refpurpose>
+ Retrieve rows from a table or view.
+ </refpurpose></refnamediv>
+ <refsynopsisdiv>
+ <refsynopsisdivinfo>
+ <date>1998-09-06</date>
+ </refsynopsisdivinfo>
+ <synopsis>
SELECT [ALL|DISTINCT]
- <REPLACEABLE CLASS="PARAMETER">expression</REPLACEABLE> [AS <REPLACEABLE CLASS="PARAMETER">name</REPLACEABLE>] [, ...]
- [INTO [TABLE] <REPLACEABLE CLASS="PARAMETER">intable</REPLACEABLE>]
- [FROM <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE> [<REPLACEABLE CLASS="PARAMETER">alias</REPLACEABLE>] [, ...] ]
- [WHERE <REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE>]
- [GROUP BY <REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE> [, ...] ]
- [HAVING <REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE> [, ...] ]
- [UNION [ALL] <REPLACEABLE CLASS="PARAMETER">select</REPLACEABLE>]
- [ORDER BY <REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE> [ASC | DESC] [, ...] ]
-</SYNOPSIS>
-
-<REFSECT2 ID="R2-SQL-SELECT-1">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-Inputs
-</TITLE>
-
-<PARA>
-<VARIABLELIST>
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">expression</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
- The name of a table's column or an expression.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">name</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
- Specifies another name for a column or an expression using
- the AS clause. <REPLACEABLE CLASS="PARAMETER">name</REPLACEABLE> cannot be used in the WHERE
- condition. It can, however, be referenced in associated
- ORDER BY or GROUP BY clauses.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">intable</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
- If the INTO TABLE clause is specified, the result of the
- query will be stored in another table with the indicated
- name.
-If <REPLACEABLE CLASS="PARAMETER">intable</REPLACEABLE> does not exist, it will be created automatically.
-
-<Note>
-<Para>
-The CREATE TABLE AS statement will also create a new table from a select query.
-</Para>
-</Note>
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
- The name of an existing table referenced by FROM clause.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">alias</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
-An alternate name for the preceeding <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE>.
-Used for brevity or to eliminate ambiguity for joins within a single table.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
-An expression leading to a boolean (true/false) result.
-See the WHERE clause.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
- The name of a table's column.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<REPLACEABLE CLASS="PARAMETER">select</REPLACEABLE>
-</TERM>
-<LISTITEM>
-<PARA>
-A select statement with all features except the ORDER BY clause.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-</VARIABLELIST>
-</PARA>
-</REFSECT2>
-
-<REFSECT2 ID="R2-SQL-SELECT-2">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-Outputs
-</TITLE>
-<VARIABLELIST>
-<VARLISTENTRY>
-<TERM>
- Rows
-</TERM>
-<LISTITEM>
-<PARA>
-The complete set of rows resulting from the query specification.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-
-<VARLISTENTRY>
-<TERM>
-<ReturnValue>count</ReturnValue>
-</TERM>
-<LISTITEM>
-<PARA>
-The count of rows returned by the query.
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-</VARIABLELIST>
-
-</REFSECT2>
-</REFSYNOPSISDIV>
-
-<REFSECT1 ID="R1-SQL-SELECT-1">
-<REFSECT1INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT1INFO>
-<TITLE>
-Description
-</TITLE>
-<PARA>
-SELECT is the principal means to access information
- in <productname>Postgres</productname>.
-
+ <replaceable class="PARAMETER">expression</replaceable> [AS <replaceable class="PARAMETER">name</replaceable>] [, ...]
+ [INTO [TABLE] <replaceable class="PARAMETER">intable</replaceable>]
+ [FROM <replaceable class="PARAMETER">table</replaceable> [<replaceable class="PARAMETER">alias</replaceable>] [, ...] ]
+ [WHERE <replaceable class="PARAMETER">condition</replaceable>]
+ [GROUP BY <replaceable class="PARAMETER">column</replaceable> [, ...] ]
+ [HAVING <replaceable class="PARAMETER">condition</replaceable> [, ...] ]
+ [UNION [ALL] <replaceable class="PARAMETER">select</replaceable>]
+ [ORDER BY <replaceable class="PARAMETER">column</replaceable> [ASC | DESC] [, ...] ]
+ </synopsis>
+
+ <refsect2 id="R2-SQL-SELECT-1">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ Inputs
+ </title>
+
+ <para>
+ <variablelist>
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">expression</replaceable>
+ </term>
+ <listitem>
+ <para>
+ The name of a table's column or an expression.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">name</replaceable>
+ </term>
+ <listitem>
+ <para>
+ Specifies another name for a column or an expression using
+ the AS clause. <replaceable class="PARAMETER">name</replaceable>
+ cannot be used in the WHERE
+ condition. It can, however, be referenced in associated
+ ORDER BY or GROUP BY clauses.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">intable</replaceable>
+ </term>
+ <listitem>
+ <para>
+ If the INTO TABLE clause is specified, the result of the
+ query will be stored in another table with the indicated
+ name.
+ If <replaceable class="PARAMETER">intable</replaceable> does
+ not exist, it will be created automatically.
+
+ <note>
+ <para>
+ The <command>CREATE TABLE AS</command> statement will also
+ create a new table from a select query.
+ </para>
+ </note>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">table</replaceable>
+ </term>
+ <listitem>
+ <para>
+ The name of an existing table referenced by the FROM clause.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">alias</replaceable>
+ </term>
+ <listitem>
+ <para>
+ An alternate name for the preceding
+ <replaceable class="PARAMETER">table</replaceable>.
+ It is used for brevity or to eliminate ambiguity for joins
+ within a single table.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">condition</replaceable>
+ </term>
+ <listitem>
+ <para>
+ A boolean expression giving a result of true or false.
+ See the WHERE clause.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">column</replaceable>
+ </term>
+ <listitem>
+ <para>
+ The name of a table's column.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <replaceable class="PARAMETER">select</replaceable>
+ </term>
+ <listitem>
+ <para>
+ A select statement with all features except the ORDER BY clause.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ </variablelist>
+ </para>
+ </refsect2>
+
+ <refsect2 id="R2-SQL-SELECT-2">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ Outputs
+ </title>
+ <variablelist>
+ <varlistentry>
+ <term>
+ Rows
+ </term>
+ <listitem>
+ <para>
+ The complete set of rows resulting from the query specification.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
+ <returnvalue>count</returnvalue>
+ </term>
+ <listitem>
+ <para>
+ The count of rows returned by the query.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+
+ </refsect2>
+ </refsynopsisdiv>
+
+ <refsect1 id="R1-SQL-SELECT-1">
+ <refsect1info>
+ <date>1998-09-06</date>
+ </refsect1info>
+ <title>
+ Description
+ </title>
+ <para>
SELECT will get all rows which satisfy the WHERE condition
- or all rows of a table if WHERE is omitted.
-
-<PARA>
+ or all rows of a table if WHERE is omitted.</para>
+
+ <para>
The GROUP BY clause allows a user to divide a table
- conceptually into groups. (See GROUP BY clause).
-
+ conceptually into groups. (See GROUP BY clause).</para>
+
+ <para>
The HAVING clause specifies a grouped table derived by the
elimination of groups from the result of the previously
- specified clause. (See HAVING clause).
-
+ specified clause. (See HAVING clause).</para>
+
+ <para>
The ORDER BY clause allows a user to specify that he/she
wishes the rows sorted according to the ASCending or
- DESCending mode operator. (See ORDER BY clause)
-
+ DESCending mode operator. (See ORDER BY clause)</para>
+
+ <para>
The UNION clause specifies a table derived from a Cartesian
- product union join. (See UNION clause).
-
-<PARA>
+ product union join. (See UNION clause).</para>
+
+ <para>
You must have SELECT privilege to a table to read its values
- (See GRANT/REVOKE statements).
-
-<REFSECT2 ID="R2-SQL-WHERE-2">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-WHERE clause
-</TITLE>
-<PARA>
- The optional WHERE condition has the general form:
-
-<Synopsis>
-WHERE <REPLACEABLE CLASS="PARAMETER">expr</REPLACEABLE> <REPLACEABLE CLASS="PARAMETER">cond_op</REPLACEABLE> <REPLACEABLE CLASS="PARAMETER">expr</REPLACEABLE> [<REPLACEABLE CLASS="PARAMETER">log_op</REPLACEABLE> ...]
-</Synopsis>
-
- where <REPLACEABLE CLASS="PARAMETER">cond_op</REPLACEABLE> can be one of: =, <, <=, >, >=, <>
- or a conditional operator like ALL, ANY, IN, LIKE, et cetera
- and <REPLACEABLE CLASS="PARAMETER">log_op</REPLACEABLE> can be one of: AND, OR, NOT.
- The comparison returns either TRUE or FALSE and all
- instances will be discarded
- if the expression evaluates to FALSE.
-</PARA>
-</REFSECT2>
-
-<REFSECT2 ID="R2-SQL-GROUPBY-2">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-GROUP BY clause
-</TITLE>
-<PARA>
+ (See GRANT/REVOKE statements).</para>
+
+ <refsect2 id="R2-SQL-WHERE-2">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ WHERE clause
+ </title>
+ <para>
+ The optional WHERE condition has the general form:
+
+ <synopsis>
+WHERE <replaceable class="PARAMETER">expr</replaceable> <replaceable class="PARAMETER">cond_op</replaceable> <replaceable class="PARAMETER">expr</replaceable> [<replaceable class="PARAMETER">log_op</replaceable> ...]
+ </synopsis>
+
+ where <replaceable class="PARAMETER">cond_op</replaceable> can be
+ one of: =, <, <=, >, >=, <>
+ or a conditional operator like ALL, ANY, IN, LIKE, et cetera
+ and <replaceable class="PARAMETER">log_op</replaceable> can be one
+ of: AND, OR, NOT.
+ The comparison returns either TRUE or FALSE and all
+ instances will be discarded
+ if the expression evaluates to FALSE.
+ </para>
+ </refsect2>
+
+ <refsect2 id="R2-SQL-GROUPBY-2">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ GROUP BY clause
+ </title>
+ <para>
GROUP BY specifies a grouped table derived by the application
of the this clause:
-<SYNOPSIS>
-GROUP BY <REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE> [, ...]
-</SYNOPSIS>
-
-<REFSECT2 ID="R2-SQL-HAVING-2">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-HAVING clause
-</TITLE>
-<PARA>
- The optional HAVING condition has the general form:
-
-<Synopsis>
-HAVING <REPLACEABLE CLASS="PARAMETER">cond_expr</REPLACEABLE>
-</Synopsis>
-
- where <REPLACEABLE CLASS="PARAMETER">cond_expr</REPLACEABLE> is the same
-as specified for the WHERE clause.
-
-<Para>
+ <synopsis>
+ GROUP BY <replaceable class="PARAMETER">column</replaceable> [, ...]
+ </synopsis></para></refsect2>
+
+ <refsect2 id="R2-SQL-HAVING-2">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ HAVING clause
+ </title>
+ <para>
+ The optional HAVING condition has the general form:
+
+ <synopsis>
+HAVING <replaceable class="PARAMETER">cond_expr</replaceable>
+ </synopsis>
+
+ where <replaceable class="PARAMETER">cond_expr</replaceable> is the same
+ as specified for the WHERE clause.</para>
+
+ <para>
HAVING specifies a grouped table derived by the elimination
of groups from the result of the previously specified clause
- that do not meet the <REPLACEABLE CLASS="PARAMETER">cond_expr</REPLACEABLE>.
-
-<Para>
- Each column referenced in <REPLACEABLE CLASS="PARAMETER">cond_expr</REPLACEABLE> shall unambiguously
+ that do not meet the <replaceable class="PARAMETER">cond_expr</replaceable>.</para>
+
+ <para>
+ Each column referenced in <replaceable class="PARAMETER">cond_expr</replaceable> shall unambiguously
reference a grouping column.
-</PARA>
-</REFSECT2>
-
-<REFSECT2 ID="R2-SQL-ORDERBYCLAUSE-2">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-ORDER BY clause
-</TITLE>
-<PARA>
-<Synopsis>
-ORDER BY <REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE> [ASC | DESC] [, ...]
-</Synopsis>
-
-<PARA>
-<REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE> can be either a column
-name or an ordinal number.
-<PARA>
+ </para>
+ </refsect2>
+
+ <refsect2 id="R2-SQL-ORDERBYCLAUSE-2">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ ORDER BY clause
+ </title>
+ <para>
+ <synopsis>
+ORDER BY <replaceable class="PARAMETER">column</replaceable> [ASC | DESC] [, ...]
+ </synopsis></para>
+
+ <para>
+ <replaceable class="PARAMETER">column</replaceable> can be either a column
+ name or an ordinal number.</para>
+ <para>
The ordinal numbers refers to the ordinal (left-to-right) position
of the column. This feature makes it possible to define an ordering
on the basis of a column that does not have a proper name.
This is never absolutely necessary because it is always possible assign a name
to a calculated column using the AS clause, e.g.:
-<ProgramListing>
-SELECT title, date_prod + 1 AS newlen FROM films ORDER BY newlen;
-</ProgramListing>
-
-<PARA>
+ <programlisting>
+ SELECT title, date_prod + 1 AS newlen FROM films ORDER BY newlen;
+ </programlisting></para>
+
+ <para>
The columns in the ORDER BY must appear in the SELECT clause.
Thus the following statement is illegal:
-<ProgramListing>
-SELECT name FROM distributors ORDER BY code;
-</ProgramListing>
-
-<PARA>
+ <programlisting>
+ SELECT name FROM distributors ORDER BY code;
+ </programlisting></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.
-</REFSECT2>
-
-<REFSECT2 ID="R2-SQL-UNION-2">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-UNION clause
-</TITLE>
-<PARA>
-<Synopsis>
-<REPLACEABLE CLASS="PARAMETER">table_query</REPLACEABLE> UNION [ALL] <REPLACEABLE CLASS="PARAMETER">table_query</REPLACEABLE>
- [ORDER BY <REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE> [ASC | DESC] [, ...] ]
-</Synopsis>
-
-where
- <REPLACEABLE CLASS="PARAMETER">table_query</REPLACEABLE>
- specifies any select expression without an ORDER BY clause.
-
-<PARA>
- The UNION operator specifies a table derived from a Cartesian product.
- The two tables that represent the direct operands of the UNION must
- have the same number of columns, and corresponding columns must be
- of compatible data types.
-
-<PARA>
- By default, the result of UNION does not contain any duplicate rows
- unless the ALL clause is specified.
-
-<Para>
-Multiple UNION operators in the same SELECT statement are evaluated left to right.
-Note that the ALL keyword is not global in nature, being applied only for the current pair of
-table results.
-
-</REFSECT2>
-
-<REFSECT1 ID="R1-SQL-SELECT-2">
-<TITLE>
-Usage
-</TITLE>
-<PARA>
-</PARA>
-<ProgramListing>
- --Join table films with their distributors:
- --
+ If not specified, ASC is assumed by default.</para>
+ </refsect2>
+
+ <refsect2 id="R2-SQL-UNION-2">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ UNION clause
+ </title>
+ <para>
+ <synopsis>
+<replaceable class="PARAMETER">table_query</replaceable> UNION [ALL] <replaceable class="PARAMETER">table_query</replaceable>
+ [ORDER BY <replaceable class="PARAMETER">column</replaceable> [ASC | DESC] [, ...] ]
+ </synopsis>
+
+ where
+ <replaceable class="PARAMETER">table_query</replaceable>
+ specifies any select expression without an ORDER BY clause.</para>
+
+ <para>
+ The UNION operator specifies a table derived from a Cartesian product.
+ The two tables that represent the direct operands of the UNION must
+ have the same number of columns, and corresponding columns must be
+ of compatible data types.</para>
+
+ <para>
+ By default, the result of UNION does not contain any duplicate rows
+ unless the ALL clause is specified.</para>
+
+ <para>
+ Multiple UNION operators in the same SELECT statement are evaluated left to right.
+ Note that the ALL keyword is not global in nature, being applied only for the current pair of
+ table results.</para>
+
+ </refsect2></refsect1>
+
+ <refsect1 id="R1-SQL-SELECT-2">
+ <title>
+ Usage
+ </title>
+ <para>
+ To join the table <literal>films</literal> with the table
+ <literal>distributors</literal>:
+ </para>
+ <programlisting>
SELECT f.title, f.did, d.name, f.date_prod, f.kind
FROM distributors d, films f
- WHERE f.did = d.did;
+ WHERE f.did = d.did
title |did|name | date_prod|kind
-------------------------+---+----------------+----------+----------
The King and I |109|20th Century Fox|1956-08-11|Musical
Das Boot |110|Bavaria Atelier |1981-11-11|Drama
Bed Knobs and Broomsticks|111|Walt Disney | |Musical
-</ProgramListing>
-
-<ProgramListing>
- --sum column "len" of all films group by "kind":
- --
+ </programlisting>
+ <para>
+ To sum the column <literal>len</literal> of all films and group
+ the reults by <literal>kind</literal>:
+ </para>
+ <programlisting>
SELECT kind, SUM(len) AS total FROM films GROUP BY kind;
kind |total
Drama | 14:28
Musical | 06:42
Romantic | 04:38
-</ProgramListing>
-
-<ProgramListing>
- --sum column length of all films group by "kind"
- --having total duration < 5 hours:
- --
+ </programlisting>
+
+ <para>
+ To sum the column <literal>len</literal> of all films, group
+ the reults by <literal>kind</literal> and show those group totals
+ that are less than 5 hours:
+ </para>
+ <programlisting>
SELECT kind, SUM(len) AS total
FROM films
GROUP BY kind
----------+------
Comedy | 02:58
Romantic | 04:38
-</ProgramListing>
-
-<ProgramListing>
- --The following two examples are identicals:
- --
+ </programlisting>
+ <para>
+ The following two examples are identical ways of sorting the individual
+ results according to the contents of the second column
+ (<literal>name</literal>):
+ </para>
+ <programlisting>
SELECT * FROM distributors ORDER BY name;
SELECT * FROM distributors ORDER BY 2;
111|Walt Disney
112|Warner Bros.
108|Westward
-</ProgramListing>
-
-<ProgramListing>
- --union of table distributors and table actors:
- -- (only those that begin with letter W):
- --
- -- distributors: actors:
+ </programlisting>
+
+ <para>
+ This example shows how to obtain the union of the tables
+ <literal>distributors</literal> and
+ <literal>actors</literal>, restricting the results to those that begin
+ with letter W in each table. Only distinct rows are to be used, so the
+ ALL keyword is omitted:
+ </para>
+ <programlisting>
+ -- distributors: actors:
-- did|name id|name
-- ---+------------ --+--------------
-- 108|Westward 1|Woody Allen
-- 111|Walt Disney 2|Warren Beatty
-- 112|Warner Bros. 3|Walter Matthau
-- ... ...
- --
- --select only distinct rows (without ALL):
- --
+
SELECT distributors.name
FROM distributors
WHERE distributors.name LIKE 'W%'
UNION
SELECT actors.name
FROM actors
- WHERE actors.name LIKE 'W%';
+ WHERE actors.name LIKE 'W%'
name
--------------
Warren Beatty
Westward
Woody Allen
-</ProgramListing>
-
-</REFSECT1>
-
-<REFSECT1 ID="R1-SQL-SELECT-3">
-<TITLE>
-Compatibility
-</TITLE>
-<PARA>
-</PARA>
-
-<REFSECT2 ID="R2-SQL-SELECT-4">
-<REFSECT2INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT2INFO>
-<TITLE>
-<Acronym>SQL92</Acronym>
-</TITLE>
-<PARA>
-</PARA>
-
-<REFSECT3 ID="R3-SQL-SELECT-1">
-<REFSECT3INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT3INFO>
-<TITLE>
-SELECT clause
-</TITLE>
-<PARA>
-In the <Acronym>SQL92</Acronym> standard, the optional keyword "AS" is just noise and can be
-omitted without affecting the meaning.
-The <ProductName>Postgres</ProductName> parser requires this keyword when
-renaming columns because the type extensibility features lead to parsing ambiguities
-in this context.
-
-<PARA>
-In the <Acronym>SQL92</Acronym> standard, the new column name specified in an
-"AS" clause may be referenced in GROUP BY and HAVING clauses. This is not currently
-allowed in <ProductName>Postgres</ProductName>.
-</PARA>
-</REFSECT3>
-
-<REFSECT3 ID="R3-SQL-UNION-1">
-<REFSECT3INFO>
-<DATE>1998-04-15</DATE>
-</REFSECT3INFO>
-<TITLE>
-UNION clause
-</TITLE>
-<PARA>
-The <Acronym>SQL92</Acronym> syntax for UNION allows an additional CORRESPONDING BY clause:
-<Synopsis>
-<REPLACEABLE CLASS="PARAMETER">table_query</REPLACEABLE> UNION [ALL]
- [CORRESPONDING [BY (<REPLACEABLE CLASS="PARAMETER">column</REPLACEABLE> [,...])]]
- <REPLACEABLE CLASS="PARAMETER">table_query</REPLACEABLE>
-</Synopsis>
-
-<Para>
-The CORRESPONDING BY clause is not supported by <ProductName>Postgres</ProductName>.
-</PARA>
-</REFSECT3>
-
-</REFSECT2>
-</REFSECT1>
-</REFENTRY>
-
-<!--
-<REPLACEABLE CLASS="PARAMETER">
-</REPLACEABLE>
-<ReturnValue></ReturnValue>
-<PARA>
-</PARA>
-<VARIABLELIST>
-<VARLISTENTRY>
-<TERM>•
-</TERM>
-<LISTITEM>
-<PARA>
-</PARA>
-</LISTITEM>
-</VARLISTENTRY>
-</VARIABLELIST>
-<PARA>
-</PARA>
+ </programlisting>
+
+ </refsect1>
+
+ <refsect1 id="R1-SQL-SELECT-3">
+ <title>
+ Compatibility
+ </title>
+ <para>
+ </para>
+
+ <refsect2 id="R2-SQL-SELECT-4">
+ <refsect2info>
+ <date>1998-09-06</date>
+ </refsect2info>
+ <title>
+ <acronym>SQL92</acronym>
+ </title>
+ <para>
+ </para>
+
+ <refsect3 id="R3-SQL-SELECT-1">
+ <refsect3info>
+ <date>1998-04-15</date>
+ </refsect3info>
+ <title>
+ SELECT clause
+ </title>
+ <para>
+ In the <acronym>SQL92</acronym> standard, the optional keyword "AS"
+ is just noise and can be
+ omitted without affecting the meaning.
+ The <productname>Postgres</productname> parser requires this keyword when
+ renaming columns because the type extensibility features lead to
+ parsing ambiguities
+ in this context.</para>
+
+ <para>
+ In the <acronym>SQL92</acronym> standard, the new column name
+ specified in an
+ "AS" clause may be referenced in GROUP BY and HAVING clauses.
+ This is not currently
+ allowed in <productname>Postgres</productname>.
+ </para>
+ </refsect3>
+
+ <refsect3 id="R3-SQL-UNION-1">
+ <refsect3info>
+ <date>1998-09-06</date>
+ </refsect3info>
+ <title>
+ UNION clause
+ </title>
+ <para>
+ The <acronym>SQL92</acronym> syntax for UNION allows an
+ additional CORRESPONDING BY clause:
+ <synopsis>
+<replaceable class="PARAMETER">table_query</replaceable> UNION [ALL]
+ [CORRESPONDING [BY (<replaceable class="PARAMETER">column</replaceable> [,...])]]
+ <replaceable class="PARAMETER">table_query</replaceable>
+ </synopsis></para>
+
+ <para>
+ The CORRESPONDING BY clause is not supported by
+ <productname>Postgres</productname>.
+ </para>
+ </refsect3>
+
+ </refsect2>
+ </refsect1>
+</refentry>
+
+<!-- Keep this comment at the end of the file
+Local variables:
+mode: sgml
+sgml-omittag:t
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:1
+sgml-indent-data:t
+sgml-parent-document:nil
+sgml-default-dtd-file:"../reference.ced"
+sgml-exposed-tags:nil
+sgml-local-catalogs:"/usr/lib/sgml/catalog"
+sgml-local-ecat-files:nil
+End:
-->
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