mirror of
https://github.com/postgres/postgres.git
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Include mention of CASE, COALESCE, and IFNULL.
Add date/time parsing procedure (perhaps should be in appendix). Add time zone information (ditto). Update keyword list.
This commit is contained in:
Thomas G. Lockhart
@@ -1,62 +1,73 @@
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<chapter>
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<title>SQL Syntax</title>
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<chapter>
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<title>SQL Syntax</title>
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<sect1>
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<title>Key Words</title>
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<abstract>
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<para>
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<acronym>SQL</acronym> manipulates sets of data. The language is
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composed of various <firstterm>key words</firstterm>. Arithmetic
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and procedural expressions are allowed. We will cover these topics
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in this chapter; subsequent chapters will include details on data
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types, functions, and operators.
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</para>
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</abstract>
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<para>
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<acronym>SQL92</acronym> defines <firstterm>key words</firstterm>
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for the language
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which have specific meaning. Some key words are
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<firstterm>reserved</firstterm>, which indicates that they are
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restricted to appear in only certain contexts. Other key words are
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<firstterm>not restricted</firstterm>, which indicates that in certain
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contexts they
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have a specific meaning but are not otherwise constrained.
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</para>
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<sect1>
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<title>Key Words</title>
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<para>
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<productname>Postgres</productname> implements an extended subset of the
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<acronym>SQL92</acronym> and <acronym>SQL3</acronym> languages. Some language
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elements are not as restricted in this implementation as is
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called for in the language standards, in part due
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to the extensibility features of <productname>Postgres</productname>.
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</para>
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<para>
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<acronym>SQL92</acronym> defines <firstterm>key words</firstterm>
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for the language
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which have specific meaning. Some key words are
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<firstterm>reserved</firstterm>, which indicates that they are
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restricted to appear in only certain contexts. Other key words are
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<firstterm>not restricted</firstterm>, which indicates that in certain
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contexts they
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have a specific meaning but are not otherwise constrained.
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</para>
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<para>
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Information on <acronym>SQL92</acronym> and <acronym>SQL3</acronym> key words
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is derived from <xref linkend="DATE97" endterm="DATE97">.
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</para>
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<para>
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<productname>Postgres</productname> implements an extended subset of the
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<acronym>SQL92</acronym> and <acronym>SQL3</acronym> languages. Some language
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elements are not as restricted in this implementation as is
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called for in the language standards, in part due
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to the extensibility features of <productname>Postgres</productname>.
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</para>
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<sect2>
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<title>Reserved Key Words</title>
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<para>
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Information on <acronym>SQL92</acronym> and <acronym>SQL3</acronym> key words
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is derived from <xref linkend="DATE97" endterm="DATE97">.
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</para>
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<para>
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<acronym>SQL92</acronym> and <acronym>SQL3</acronym> have
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<firstterm>reserved key words</firstterm> which are not allowed
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as identifiers and not allowed in any usage other than as fundamental
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tokens in <acronym>SQL</acronym> statements.
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<productname>Postgres</productname> has additional key words
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which have similar restrictions. In particular, these key words
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are not allowed as column or table names, though in some cases
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they are allowed to be column labels (i.e. in AS clauses).
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</para>
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<sect2>
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<title>Reserved Key Words</title>
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<tip>
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<para>
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Any string can be specified as an identifier if surrounded by
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double quotes (<quote>like this!</quote>). Some care is required since
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such an identifier will be case sensitive
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and will retain embedded whitespace other special characters.</para>
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</tip>
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<para>
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<acronym>SQL92</acronym> and <acronym>SQL3</acronym> have
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<firstterm>reserved key words</firstterm> which are not allowed
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as identifiers and not allowed in any usage other than as fundamental
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tokens in <acronym>SQL</acronym> statements.
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<productname>Postgres</productname> has additional key words
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which have similar restrictions. In particular, these key words
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are not allowed as column or table names, though in some cases
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they are allowed to be column labels (i.e. in AS clauses).
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</para>
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<para>
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The following are <productname>Postgres</productname>
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reserved words which are neither <acronym>SQL92</acronym>
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nor <acronym>SQL3</acronym> reserved words. These are allowed
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to be present as column labels, but not as identifiers:
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<tip>
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<para>
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Any string can be specified as an identifier if surrounded by
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double quotes (<quote>like this!</quote>). Some care is required since
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such an identifier will be case sensitive
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and will retain embedded whitespace other special characters.
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</para>
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</tip>
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<programlisting>
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<para>
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The following are <productname>Postgres</productname>
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reserved words which are neither <acronym>SQL92</acronym>
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nor <acronym>SQL3</acronym> reserved words. These are allowed
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to be present as column labels, but not as identifiers:
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<programlisting>
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ABORT ANALYZE
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BINARY
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CLUSTER CONSTRAINT COPY
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@@ -69,32 +80,33 @@ RESET
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SETOF SHOW
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UNLISTEN UNTIL
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VACUUM VERBOSE
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</programlisting>
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</para>
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</programlisting>
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</para>
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<para>
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The following are <productname>Postgres</productname>
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reserved words which are also <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved words, and which
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are allowed to be present as column labels, but not as identifiers:
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<para>
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The following are <productname>Postgres</productname>
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reserved words which are also <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved words, and which
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are allowed to be present as column labels, but not as identifiers:
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<programlisting>
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<programlisting>
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CASE COALESCE CROSS CURRENT
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ELSE END
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FALSE FOREIGN
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GROUP
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GLOBAL GROUP
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LOCAL
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NULLIF
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ORDER
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POSITION PRECISION
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TABLE THEN TRANSACTION TRUE
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WHEN
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</programlisting>
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</programlisting>
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The following are <productname>Postgres</productname>
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reserved words which are also <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved words:
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The following are <productname>Postgres</productname>
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reserved words which are also <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved words:
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<programlisting>
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<programlisting>
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ADD ALL ALTER AND ANY AS ASC
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BEGIN BETWEEN BOTH BY
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CASCADE CAST CHAR CHARACTER CHECK CLOSE
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@@ -118,49 +130,49 @@ TO TRAILING TRIM
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UNION UNIQUE UPDATE USER USING
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VALUES VARCHAR VARYING VIEW
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WHERE WITH WORK
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</programlisting>
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</para>
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</programlisting>
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</para>
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<para>
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The following are <acronym>SQL92</acronym> reserved key words which
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are not <productname>Postgres</productname> reserved key words, but which
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if used as function names are always translated into the function
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<function>length</function>:
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<para>
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The following are <acronym>SQL92</acronym> reserved key words which
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are not <productname>Postgres</productname> reserved key words, but which
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if used as function names are always translated into the function
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<function>length</function>:
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<programlisting>
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<programlisting>
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CHAR_LENGTH CHARACTER_LENGTH
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</programlisting>
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</para>
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</programlisting>
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</para>
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<para>
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The following are <acronym>SQL92</acronym> or <acronym>SQL3</acronym>
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reserved key words which
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are not <productname>Postgres</productname> reserved key words, but
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if used as type names are always translated into an alternate, native type:
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<para>
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The following are <acronym>SQL92</acronym> or <acronym>SQL3</acronym>
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reserved key words which
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are not <productname>Postgres</productname> reserved key words, but
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if used as type names are always translated into an alternate, native type:
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<programlisting>
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<programlisting>
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BOOLEAN DOUBLE FLOAT INT INTEGER INTERVAL REAL SMALLINT
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</programlisting>
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</para>
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</programlisting>
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</para>
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<para>
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The following are either <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved key words
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which are not key words in <productname>Postgres</productname>.
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These have no proscribed usage in <productname>Postgres</productname>
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at the time of writing (v6.4) but may become reserved key words in the
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future:
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<para>
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The following are either <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved key words
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which are not key words in <productname>Postgres</productname>.
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These have no proscribed usage in <productname>Postgres</productname>
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at the time of writing (v6.5) but may become reserved key words in the
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future:
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<note>
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<para>
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Some of these key words represent functions in <acronym>SQL92</acronym>.
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These functions are defined in <productname>Postgres</productname>,
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but the parser does not consider the names to be key words and they are allowed
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in other contexts.
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</para>
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</note>
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<note>
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<para>
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Some of these key words represent functions in <acronym>SQL92</acronym>.
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These functions are defined in <productname>Postgres</productname>,
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but the parser does not consider the names to be key words and they are allowed
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in other contexts.
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</para>
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</note>
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<programlisting>
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<programlisting>
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ALLOCATE ARE ASSERTION AT AUTHORIZATION AVG
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BIT BIT_LENGTH
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CASCADED CATALOG COLLATION CONNECT CONNECTION
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@@ -168,7 +180,7 @@ CASCADED CATALOG COLLATION CONNECT CONNECTION
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DATE DEALLOCATE DEC DESCRIBE DESCRIPTOR DIAGNOSTICS DISCONNECT DOMAIN
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END-EXEC ESCAPE EXCEPT EXCEPTION EXEC EXTERNAL
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FIRST FOUND
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GET GLOBAL GO GOTO
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GET GO GOTO
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IDENTITY IMMEDIATE INDICATOR INITIALLY INPUT INTERSECT ISOLATION
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LAST LEVEL LOWER
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MAX MIN MODULE
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@@ -181,56 +193,56 @@ TEMPORARY TRANSLATE TRANSLATION
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UNKNOWN UPPER USAGE
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VALUE
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WHENEVER WRITE
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</programlisting>
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</para>
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</sect2>
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</programlisting>
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</para>
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</sect2>
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<sect2>
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<title>Non-reserved Keywords</title>
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<sect2>
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<title>Non-reserved Keywords</title>
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<para>
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<acronym>SQL92</acronym> and <acronym>SQL3</acronym> have
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<firstterm>non-reserved keywords</firstterm> which have
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a proscribed meaning in the language but which are also allowed
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as identifiers.
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<productname>Postgres</productname> has additional keywords
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which allow similar unrestricted usage.
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In particular, these keywords
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are allowed as column or table names.
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</para>
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<para>
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<acronym>SQL92</acronym> and <acronym>SQL3</acronym> have
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<firstterm>non-reserved keywords</firstterm> which have
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a proscribed meaning in the language but which are also allowed
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as identifiers.
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<productname>Postgres</productname> has additional keywords
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which allow similar unrestricted usage.
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In particular, these keywords
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are allowed as column or table names.
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</para>
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<para>
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The following are <productname>Postgres</productname>
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non-reserved key words which are neither <acronym>SQL92</acronym>
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nor <acronym>SQL3</acronym> non-reserved key words:
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<para>
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The following are <productname>Postgres</productname>
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non-reserved key words which are neither <acronym>SQL92</acronym>
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nor <acronym>SQL3</acronym> non-reserved key words:
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<programlisting>
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AFTER AGGREGATE
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<programlisting>
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ACCESS AFTER AGGREGATE
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BACKWARD BEFORE
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CACHE CREATEDB CREATEUSER CYCLE
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DATABASE DELIMITERS
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EACH ENCODING
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EACH ENCODING EXCLUSIVE
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FORWARD FUNCTION
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HANDLER
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INCREMENT INDEX INHERITS INSENSITIVE INSTEAD ISNULL
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LANCOMPILER LOCATION
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MAXVALUE MINVALUE
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MAXVALUE MINVALUE MODE
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NOCREATEDB NOCREATEUSER NOTHING NOTNULL
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OIDS OPERATOR
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PASSWORD PROCEDURAL
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RECIPE RENAME RETURNS ROW RULE
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SEQUENCE SERIAL START STATEMENT STDIN STDOUT
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SEQUENCE SERIAL SHARE START STATEMENT STDIN STDOUT
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TRUSTED
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VALID VERSION
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</programlisting>
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</para>
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</programlisting>
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</para>
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<para>
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The following are <productname>Postgres</productname>
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non-reserved key words which are <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved key words:
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<para>
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The following are <productname>Postgres</productname>
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non-reserved key words which are <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> reserved key words:
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<programlisting>
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<programlisting>
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ABSOLUTE ACTION
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DAY
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HOUR
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@@ -246,30 +258,30 @@ SCROLL SECOND
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TIME TIMESTAMP TIMEZONE_HOUR TIMEZONE_MINUTE TRIGGER
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YEAR
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ZONE
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</programlisting>
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</para>
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</programlisting>
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</para>
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<para>
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The following are <productname>Postgres</productname>
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non-reserved key words which are also either <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> non-reserved key words:
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<para>
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The following are <productname>Postgres</productname>
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non-reserved key words which are also either <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> non-reserved key words:
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<programlisting>
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TYPE
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</programlisting>
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</para>
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<programlisting>
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COMMITTED SERIALIZABLE TYPE
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</programlisting>
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</para>
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<para>
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The following are either <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> non-reserved key words which are not
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key words of any kind in <productname>Postgres</productname>:
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<para>
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The following are either <acronym>SQL92</acronym>
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or <acronym>SQL3</acronym> non-reserved key words which are not
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key words of any kind in <productname>Postgres</productname>:
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<programlisting>
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<programlisting>
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ADA
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C CATALOG_NAME CHARACTER_SET_CATALOG CHARACTER_SET_NAME
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CHARACTER_SET_SCHEMA CLASS_ORIGIN COBOL COLLATION_CATALOG
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COLLATION_NAME COLLATION_SCHEMA COLUMN_NAME
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COMMAND_FUNCTION COMMITTED CONDITION_NUMBER
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COMMAND_FUNCTION CONDITION_NUMBER
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CONNECTION_NAME CONSTRAINT_CATALOG CONSTRAINT_NAME
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CONSTRAINT_SCHEMA CURSOR_NAME
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DATA DATE_TIME_INTERVAL_CODE DATE_TIME_INTERVAL_PRECISION
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@@ -281,15 +293,29 @@ NAME NULLABLE NUMBER
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PAD PASCAL PLI
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REPEATABLE RETURNED_LENGTH RETURNED_OCTET_LENGTH
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RETURNED_SQLSTATE ROW_COUNT
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SCALE SCHEMA_NAME SERIALIZABLE SERVER_NAME SPACE
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SCALE SCHEMA_NAME SERVER_NAME SPACE
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SUBCLASS_ORIGIN
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TABLE_NAME
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UNCOMMITTED UNNAMED
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</programlisting>
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</para>
|
||||
</sect2>
|
||||
</sect1>
|
||||
</chapter>
|
||||
</programlisting>
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||||
</para>
|
||||
</sect2>
|
||||
</sect1>
|
||||
|
||||
<sect1>
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||||
<title>Expressions</title>
|
||||
|
||||
<para>
|
||||
<acronym>SQL92</acronym> allows <firstterm>expressions</firstterm>
|
||||
to transform data in expressions. Expressions may contain operators
|
||||
(see <xref linkend="operators-title" endterm="operators-title">
|
||||
for more details) and functions
|
||||
(<xref linkend="functions-title" endterm="functions-title"> has
|
||||
more information).
|
||||
|
||||
</para>
|
||||
</sect1>
|
||||
</chapter>
|
||||
|
||||
<!-- Keep this comment at the end of the file
|
||||
Local variables:
|
||||
|
||||
Reference in New Issue
Block a user