ascii(string)
| int | ASCII code of the first character of the
argument. For UTF8 returns the Unicode code
point of the character. For other multibyte encodings, the
argument must be an ASCII character.
| ascii('x') | 120 |
btrim(string text
[, characters text])
| text | Remove the longest string consisting only of characters
in characters (a space by default)
from the start and end of string
| btrim('xyxtrimyyx', 'xy') | trim |
chr(int)
| text | Character with the given code. For UTF8 the
argument is treated as a Unicode code point. For other multibyte
encodings the argument must designate an
ASCII character. The NULL (0) character is not
allowed because text data types cannot store such bytes.
| chr(65) | A |
concat(str "any"
[, str "any" [, ...] ])
| text | Concatenate all arguments. NULL arguments are ignored.
| concat('abcde', 2, NULL, 22) | abcde222 |
concat_ws(sep text,
str "any"
[, str "any" [, ...] ])
| text | Concatenate all but first arguments with separators. The first
parameter is used as a separator. NULL arguments are ignored.
| concat_ws(',', 'abcde', 2, NULL, 22) | abcde,2,22 |
convert(string bytea,
src_encoding name,
dest_encoding name)
| bytea | Convert string to dest_encoding. The
original encoding is specified by
src_encoding. The
string must be valid in this encoding.
Conversions can be defined by CREATE CONVERSION.
Also there are some predefined conversions. See Table 9-8 for available conversions.
| convert('text_in_utf8', 'UTF8', 'LATIN1') | text_in_utf8 represented in Latin-1
encoding (ISO 8859-1) |
convert_from(string bytea,
src_encoding name)
| text | Convert string to the database encoding. The original encoding
is specified by src_encoding. The
string must be valid in this encoding.
| convert_from('text_in_utf8', 'UTF8') | text_in_utf8 represented in the current database encoding |
convert_to(string text,
dest_encoding name)
| bytea | Convert string to dest_encoding.
| convert_to('some text', 'UTF8') | some text represented in the UTF8 encoding |
decode(string text,
format text)
| bytea | Decode binary data from textual representation in string.
Options for format are same as in encode.
| decode('MTIzAAE=', 'base64') | \x3132330001 |
encode(data bytea,
format text)
| text | Encode binary data into a textual representation. Supported
formats are: base64, hex, escape.
escape converts zero bytes and high-bit-set bytes to
octal sequences (\nnn) and
doubles backslashes.
| encode(E'123\\000\\001', 'base64') | MTIzAAE= |
format(formatstr text
[, str "any" [, ...] ])
| text | Format a string. This function is similar to the C function
sprintf; but only the following conversion specifications
are recognized: %s interpolates the corresponding
argument as a string; %I escapes its argument as
an SQL identifier; %L escapes its argument as an
SQL literal; %% outputs a literal %.
A conversion can reference an explicit parameter position by preceding
the conversion specifier with n$, where
n is the argument position.
See also Example 39-1.
| format('Hello %s, %1$s', 'World') | Hello World, World |
initcap(string)
| text | Convert the first letter of each word to upper case and the
rest to lower case. Words are sequences of alphanumeric
characters separated by non-alphanumeric characters.
| initcap('hi THOMAS') | Hi Thomas |
left(str text,
n int)
| text | Return first n characters in the string. When n
is negative, return all but last |n| characters.
| left('abcde', 2) | ab |
length(string)
| int | Number of characters in string
| length('jose') | 4 |
length(string bytea,
encoding name ) | int | Number of characters in string in the given
encoding. The string
must be valid in this encoding.
| length('jose', 'UTF8') | 4 |
lpad(string text,
length int
[, fill text])
| text | Fill up the string to length
length by prepending the characters
fill (a space by default). If the
string is already longer than
length then it is truncated (on the
right).
| lpad('hi', 5, 'xy') | xyxhi |
ltrim(string text
[, characters text])
| text | Remove the longest string containing only characters from
characters (a space by default) from the start of
string
| ltrim('zzzytrim', 'xyz') | trim |
md5(string)
| text | Calculates the MD5 hash of string,
returning the result in hexadecimal
| md5('abc') | 900150983cd24fb0 d6963f7d28e17f72 |
pg_client_encoding()
| name | Current client encoding name
| pg_client_encoding() | SQL_ASCII |
quote_ident(string text)
| text | Return the given string suitably quoted to be used as an identifier
in an SQL statement string.
Quotes are added only if necessary (i.e., if the string contains
non-identifier characters or would be case-folded).
Embedded quotes are properly doubled.
See also Example 39-1.
| quote_ident('Foo bar') | "Foo bar" |
quote_literal(string text)
| text | Return the given string suitably quoted to be used as a string literal
in an SQL statement string.
Embedded single-quotes and backslashes are properly doubled.
Note that quote_literal returns null on null
input; if the argument might be null,
quote_nullable is often more suitable.
See also Example 39-1.
| quote_literal(E'O\'Reilly') | 'O''Reilly' |
quote_literal(value anyelement) | text | Coerce the given value to text and then quote it as a literal.
Embedded single-quotes and backslashes are properly doubled.
| quote_literal(42.5) | '42.5' |
quote_nullable(string text)
| text | Return the given string suitably quoted to be used as a string literal
in an SQL statement string; or, if the argument
is null, return NULL.
Embedded single-quotes and backslashes are properly doubled.
See also Example 39-1.
| quote_nullable(NULL) | NULL |
quote_nullable(value anyelement) | text | Coerce the given value to text and then quote it as a literal;
or, if the argument is null, return NULL.
Embedded single-quotes and backslashes are properly doubled.
| quote_nullable(42.5) | '42.5' |
regexp_matches(string text, pattern text [, flags text])
| setof text[] | Return all captured substrings resulting from matching a POSIX regular
expression against the string. See
Section 9.7.3 for more information.
| regexp_matches('foobarbequebaz', '(bar)(beque)') | {bar,beque} |
regexp_replace(string text, pattern text, replacement text [, flags text])
| text | Replace substring(s) matching a POSIX regular expression. See
Section 9.7.3 for more information.
| regexp_replace('Thomas', '.[mN]a.', 'M') | ThM |
regexp_split_to_array(string text, pattern text [, flags text ])
| text[] | Split string using a POSIX regular expression as
the delimiter. See Section 9.7.3 for more
information.
| regexp_split_to_array('hello world', E'\\s+') | {hello,world} |
regexp_split_to_table(string text, pattern text [, flags text])
| setof text | Split string using a POSIX regular expression as
the delimiter. See Section 9.7.3 for more
information.
| regexp_split_to_table('hello world', E'\\s+') | hello world (2 rows) |
repeat(string text, number int)
| text | Repeat string the specified
number of times | repeat('Pg', 4) | PgPgPgPg |
replace(string text,
from text,
to text)
| text | Replace all occurrences in string of substring
from with substring to
| replace('abcdefabcdef', 'cd', 'XX') | abXXefabXXef |
reverse(str)
| text | Return reversed string.
| reverse('abcde') | edcba |
right(str text,
n int)
| text | Return last n characters in the string. When n
is negative, return all but first |n| characters.
| right('abcde', 2) | de |
rpad(string text,
length int
[, fill text])
| text | Fill up the string to length
length by appending the characters
fill (a space by default). If the
string is already longer than
length then it is truncated.
| rpad('hi', 5, 'xy') | hixyx |
rtrim(string text
[, characters text])
| text | Remove the longest string containing only characters from
characters (a space by default) from the end of
string
| rtrim('trimxxxx', 'x') | trim |
split_part(string text,
delimiter text,
field int)
| text | Split string on delimiter
and return the given field (counting from one)
| split_part('abc~@~def~@~ghi', '~@~', 2) | def |
strpos(string, substring)
| int | Location of specified substring (same as
position(substring in
string), but note the reversed
argument order)
| strpos('high', 'ig') | 2 |
substr(string, from [, count])
| text | Extract substring (same as
substring(string from from for count))
| substr('alphabet', 3, 2) | ph |
to_ascii(string text
[, encoding text])
| text | Convert string to ASCII from another encoding
(only supports conversion from LATIN1, LATIN2, LATIN9,
and WIN1250 encodings)
| to_ascii('Karel') | Karel |
to_hex(number int
or bigint)
| text | Convert number to its equivalent hexadecimal
representation
| to_hex(2147483647) | 7fffffff |
translate(string text,
from text,
to text)
| text | Any character in string that matches a
character in the from set is replaced by
the corresponding character in the to
set. If from is longer than
to, occurrences of the extra characters in
from are removed.
| translate('12345', '143', 'ax') | a2x5 |