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Augment info on string functions per Jose Soares' suggestions.

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This commit is contained in:
Thomas G. Lockhart 1999-01-19 16:11:18 +00:00
parent bda6246664
commit f3fde99841
1 changed files with 95 additions and 59 deletions
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154
doc/src/sgml/func.sgml
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@ -65,54 +65,86 @@ available through operators and may be documented as operators only.
</Para>
</sect1>
<sect1>
<title>String Functions</title>
<sect1>
<title>String Functions</title>
<Para>
SQL92 defines string functions with specific syntax. Some of these
are implemented using other <ProductName>Postgres</ProductName> functions.
</Para>
<Para>
SQL92 defines string functions with specific syntax. Some of these
are implemented using other <ProductName>Postgres</ProductName> functions.
The supported string types for <acronym>SQL92</acronym> are
<type>char</type>, <type>varchar</type>, and <type>text</type>.
</Para>
<Para>
<TABLE TOCENTRY="1">
<TITLE><Acronym>SQL92</Acronym> String Functions</TITLE>
<TGROUP COLS="4">
<THEAD>
<ROW>
<ENTRY>Function</ENTRY>
<ENTRY>Returns</ENTRY>
<ENTRY>Description</ENTRY>
<ENTRY>Example</ENTRY>
</ROW>
</THEAD>
<TBODY>
<ROW>
<ENTRY> position(text in text) </ENTRY>
<ENTRY> int4 </ENTRY>
<ENTRY> location of specified substring </ENTRY>
<ENTRY> position('o' in 'Tom') </ENTRY>
</ROW>
<ROW>
<ENTRY> substring(text [from int] [for int]) </ENTRY>
<ENTRY> text </ENTRY>
<ENTRY> extract specified substring </ENTRY>
<ENTRY> substring('Tom' from 2 for 2) </ENTRY>
</ROW>
<ROW>
<ENTRY> trim([leading|trailing|both] [text] from text) </ENTRY>
<ENTRY> text </ENTRY>
<ENTRY> trim characters from text </ENTRY>
<ENTRY> trim(both 'x' from 'xTomx') </ENTRY>
</ROW>
</TBODY>
</TGROUP>
</TABLE>
</Para>
<Para>
<TABLE TOCENTRY="1">
<TITLE><Acronym>SQL92</Acronym> String Functions</TITLE>
<TGROUP COLS="4">
<THEAD>
<ROW>
<ENTRY>Function</ENTRY>
<ENTRY>Returns</ENTRY>
<ENTRY>Description</ENTRY>
<ENTRY>Example</ENTRY>
</ROW>
</THEAD>
<TBODY>
<ROW>
<ENTRY> char_length(string) </ENTRY>
<ENTRY> int4 </ENTRY>
<ENTRY> length of string </ENTRY>
<ENTRY> char_length('jose') </ENTRY>
</ROW>
<ROW>
<ENTRY> character_length(string) </ENTRY>
<ENTRY> int4 </ENTRY>
<ENTRY> length of string </ENTRY>
<ENTRY> char_length('jose') </ENTRY>
</ROW>
<ROW>
<ENTRY> lower(string) </ENTRY>
<ENTRY> string </ENTRY>
<ENTRY> convert string to lower case </ENTRY>
<ENTRY> lower('TOM') </ENTRY>
</ROW>
<ROW>
<ENTRY> octet_length(string) </ENTRY>
<ENTRY> int4 </ENTRY>
<ENTRY> storage length of string </ENTRY>
<ENTRY> octet_length('jose') </ENTRY>
</ROW>
<ROW>
<ENTRY> position(string in string) </ENTRY>
<ENTRY> int4 </ENTRY>
<ENTRY> location of specified substring </ENTRY>
<ENTRY> position('o' in 'Tom') </ENTRY>
</ROW>
<ROW>
<ENTRY> substring(string [from int] [for int]) </ENTRY>
<ENTRY> string </ENTRY>
<ENTRY> extract specified substring </ENTRY>
<ENTRY> substring('Tom' from 2 for 2) </ENTRY>
</ROW>
<ROW>
<ENTRY> trim([leading|trailing|both] [string] from string) </ENTRY>
<ENTRY> string </ENTRY>
<ENTRY> trim characters from string </ENTRY>
<ENTRY> trim(both 'x' from 'xTomx') </ENTRY>
</ROW>
<ROW>
<ENTRY> upper(text) </ENTRY>
<ENTRY> text </ENTRY>
<ENTRY> convert text to upper case </ENTRY>
<ENTRY> upper('tom') </ENTRY>
</ROW>
</TBODY>
</TGROUP>
</TABLE>
</Para>
<Para>
Many string functions are available for text, varchar(), and char() types.
Some are used internally to implement the SQL92 string functions listed above.
</Para>
<Para>
Many additional string functions are available for text, varchar(), and char() types.
Some are used internally to implement the SQL92 string functions listed above.
</Para>
<Para>
<TABLE TOCENTRY="1">
@ -146,12 +178,6 @@ Some are used internally to implement the SQL92 string functions listed above.
<ENTRY> initcap('thomas') </ENTRY>
</ROW>
<ROW>
<ENTRY> lower(text) </ENTRY>
<ENTRY> text </ENTRY>
<ENTRY> convert text to lower case </ENTRY>
<ENTRY> lower('TOM') </ENTRY>
</ROW>
<ROW>
<ENTRY> lpad(text,int,text) </ENTRY>
<ENTRY> text </ENTRY>
<ENTRY> left pad string to specified length </ENTRY>
@ -164,9 +190,9 @@ Some are used internally to implement the SQL92 string functions listed above.
<ENTRY> ltrim('xxxxtrim','x') </ENTRY>
</ROW>
<ROW>
<ENTRY> position(text,text) </ENTRY>
<ENTRY> textpos(text,text) </ENTRY>
<ENTRY> text </ENTRY>
<ENTRY> extract specified substring </ENTRY>
<ENTRY> locate specified substring </ENTRY>
<ENTRY> position('high','ig') </ENTRY>
</ROW>
<ROW>
@ -217,12 +243,6 @@ Some are used internally to implement the SQL92 string functions listed above.
<ENTRY> convert text to varchar type </ENTRY>
<ENTRY> varchar('text string') </ENTRY>
</ROW>
<ROW>
<ENTRY> upper(text) </ENTRY>
<ENTRY> text </ENTRY>
<ENTRY> convert text to upper case </ENTRY>
<ENTRY> upper('tom') </ENTRY>
</ROW>
</TBODY>
</TGROUP>
</TABLE>
@ -689,3 +709,19 @@ support functions.
</chapter>
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