*** sgml.orig/func.sgml Mon Nov 19 01:05:01 2001
--- sgml/func.sgml Mon Nov 19 20:00:36 2001
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*** 1133,1139 ****
text
Encodes binary data to ASCII-only representation. Supported
! types are: 'base64', 'hex'.
encode('123\\000\\001', 'base64')
MTIzAAE=
--- 1133,1139 ----
text
Encodes binary data to ASCII-only representation. Supported
! types are: 'base64', 'hex', 'escape'.
encode('123\\000\\001', 'base64')
MTIzAAE=
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*** 1164,1169 ****
--- 1164,1349 ----
+
+ Binary String Functions and Operators
+
+
+ This section describes functions and operators for examining and
+ manipulating binary string values. Strings in this context include
+ values of the type BYTEA.
+
+
+
+ SQL defines some string functions with a special syntax where
+ certain keywords rather than commas are used to separate the
+ arguments. Details are in .
+ Some functions are also implemented using the regular syntax for
+ function invocation. (See .)
+
+
+
+ <acronym>SQL</acronym> Binary String Functions and Operators
+
+
+
+ Function
+ Return Type
+ Description
+ Example
+ Result
+
+
+
+
+
+ string || string
+ bytea
+
+ string concatenation
+
+ binary strings
+ concatenation
+
+
+ '\\\\Postgre'::bytea || '\\047SQL\\000'::bytea
+ \\Postgre'SQL\000
+
+
+
+ octet_length(string)
+ integer
+ number of bytes in binary string
+ octet_length('jo\\000se'::bytea)
+ 5
+
+
+
+ position(substring in string)
+ integer
+ location of specified substring
+ position('\\000om'::bytea in 'Th\\000omas'::bytea)
+ 3
+
+
+
+ substring(string from integer for integer)
+ bytea
+
+ extract substring
+
+ substring
+
+
+ substring('Th\\000omas'::bytea from 2 for 3)
+ h\000o
+
+
+
+
+ trim(both
+ characters from
+ string)
+
+ bytea
+
+ Removes the longest string containing only the
+ characters from the
+ beginning/end/both ends of the string.
+
+ trim('\\000'::bytea from '\\000Tom\\000'::bytea)
+ Tom
+
+
+
+
+
+
+
+ Additional binary string manipulation functions are available and are
+ listed below. Some of them are used internally to implement the
+ SQL-standard string functions listed above.
+
+
+
+ Other Binary String Functions
+
+
+
+ Function
+ Return Type
+ Description
+ Example
+ Result
+
+
+
+
+
+ btrim(string bytea, trim bytea)
+ bytea
+
+ Remove (trim) the longest string consisting only of characters
+ in trim from the start and end of
+ string.
+
+ btrim('\\000trim\\000'::bytea,'\\000'::bytea)
+ trim
+
+
+
+ length(string)
+ integer
+
+ length of binary string
+
+ binary strings
+ length
+
+
+ length
+ binary strings
+ binary strings, length
+
+
+ length('jo\\000se'::bytea)
+ 5
+
+
+
+
+ encode(string bytea,
+ type text)
+
+ text
+
+ Encodes binary string to ASCII-only representation. Supported
+ types are: 'base64', 'hex', 'escape'.
+
+ encode('123\\000456'::bytea, 'escape')
+ 123\000456
+
+
+
+
+ decode(string text,
+ type text)
+
+ bytea
+
+ Decodes binary string from string previously
+ encoded with encode(). Parameter type is same as in encode().
+
+ decode('123\\000456', 'escape')
+ 123\000456
+
+
+
+
+
+
+
+
+
Pattern Matching