PostgreSQL: Data Type Formatting Functions

Last update on November 13 2023 09:57:51 (UTC/GMT +8 hours)

Data Type Formatting Functions

There are various PostgreSQL formatting functions available for converting various data types (date/time, integer, floating point, numeric) to formatted strings and for converting from formatted strings to specific data types. Before discussing the formatting functions we will discuss various patterns available for formatting date and time values.

Patterns for Date/Time Formatting

Pattern	Description
HH	hour of day (01-12)
HH12	hour of day (01-12)
HH24	hour of day (00-23)
MI	minute (00-59)
SS	second (00-59)
MS	millisecond (000-999)
US	microsecond (000000-999999)
SSSS	seconds past midnight (0-86399)
AM, am, PM or pm	meridiem indicator (without periods)
A.M., a.m., P.M. or p.m.	meridiem indicator (with periods)
Y,YYY	year (4 and more digits) with comma
YYYY	year (4 and more digits)
YYY	last 3 digits of year
YY	last 2 digits of year
Y	last digit of year
IYYY	ISO year (4 and more digits)
IYY	last 3 digits of ISO year
IY	last 2 digits of ISO year
I	last digit of ISO year
BC, bc, AD or ad	era indicator (without periods)
B.C., b.c., A.D. or a.d.	era indicator (with periods)
MONTH	full upper case month name (blank-padded to 9 chars)
Month	full capitalized month name (blank-padded to 9 chars)
month	full lower case month name (blank-padded to 9 chars)
MON	abbreviated upper case month name (3 chars in English, localized lengths vary)
Mon	abbreviated capitalized month name (3 chars in English, localized lengths vary)
mon	abbreviated lower case month name (3 chars in English, localized lengths vary)
MM	month number (01-12)
DAY	full upper case day name (blank-padded to 9 chars)
Day	full capitalized day name (blank-padded to 9 chars)
day	full lower case day name (blank-padded to 9 chars)
DY	abbreviated upper case day name (3 chars in English, localized lengths vary)
Dy	abbreviated capitalized day name (3 chars in English, localized lengths vary)
dy	abbreviated lower case day name (3 chars in English, localized lengths vary)
DDD	day of year (001-366)
IDDD	ISO day of year (001-371; day 1 of the year is Monday of the first ISO week.)
DD	day of month (01-31)
D	day of the week, Sunday(1) to Saturday(7)
ID	ISO day of the week, Monday(1) to Sunday(7)
W	week of month (1-5) (The first week starts on the first day of the month.)
WW	week number of year (1-53) (The first week starts on the first day of the year.)
IW	ISO week number of year (01 - 53; the first Thursday of the new year is in week 1.)
CC	century (2 digits) (The twenty-first century starts on 2001-01-01.)
J	Julian Day (integer days since November 24, 4714 BC at midnight UTC)
Q	quarter (ignored by to_date and to_timestamp)
RM	month in upper case Roman numerals (I-XII; I=January)
rm	month in lower case Roman numerals (i-xii; i=January)
TZ	upper case time-zone name
tz	lower case time-zone name

Patterns for Numeric Formatting

Pattern	Description
9	value with the specified number of digits
0	value with leading zeros
. (period)	decimal point
, (comma)	group (thousand) separator
PR	negative value in angle brackets
S	sign anchored to number (uses locale)
L	currency symbol (uses locale)
D	decimal point (uses locale)
G	group separator (uses locale)
MI	minus sign in specified position (if number < 0)
PL	plus sign in specified position (if number > 0)
SG	plus/minus sign in specified position
RN	Roman numeral (input between 1 and 3999)
TH or th	ordinal number suffix
V	shift specified number of digits (see notes)
EEEE	exponent for scientific notation

Formatting Functions

Function	Return Type	Description	Example
to_char(timestamp, text)	text	convert time stamp to string	to_char(current_timestamp, 'HH12:MI:SS')
to_char(interval, text)	text	convert interval to string	to_char(interval '15h 2m 12s', 'HH24:MI:SS')
to_char(int, text)	text	convert integer to string	to_char(125, '999')
to_char(double precision, text)	text	convert real/double precision to string	to_char(125.8::real, '999D9')
to_char(numeric, text)	text	convert numeric to string	to_char(-125.8, '999D99S')
to_date(text, text)	date	convert string to date	to_date('05 Dec 2000', 'DD Mon YYYY')
to_number(text, text)	numeric	convert string to numeric	to_number('12,454.8-', '99G999D9S')
to_timestamp(text, text)	timestamp with time zone	convert string to time stamp	to_timestamp('05 Dec 2000', 'DD Mon YYYY')
to_timestamp(double precision)	timestamp with time zone	convert Unix epoch to time stamp	to_timestamp(1284352323)

In a to_char output template string, there are certain patterns that are recognized and replaced with appropriately-formatted.

Bit String Operators

Operator	Description
\|\|	concatenation
&	bitwise AND
\|	bitwise OR
#	bitwise XOR
~	bitwise NOT
<<	bitwise shift left
>>	bitwise shift right

Example: concatenation (||) operator

postgres=# SELECT 'w3' || 'resource';
  ?column?
------------
 w3resource
(1 row)

Example: bitwise AND (&) operator

postgres=# SELECT  2 & 15;
 ?column?
----------
        2
(1 row)

Example: bitwise OR (|) operator

postgres=# SELECT 2 | 5;
 ?column?
----------
        7
(1 row)

Example: bitwise XOR (#) operator

postgres=# SELECT  2 ^ 15;
 ?column?
----------
    32768
(1 row))

Example: bitwise NOT (~) operator

postgres=# SELECT  ~2;
 ?column?
----------
       -3
(1 row)

Example: bitwise shift left (<<) operator

postgres=# SELECT  2 << 5;
 ?column?
----------
       64
(1 row)

Example: bitwise shift right (>>) operator

postgres=# SELECT  8 >> 2;
 ?column?
----------
        2
(1 row)

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