Preamble
The to_date function in PostgreSQL converts a string into a date.
Syntax of the to_date function in PostgreSQL
to_date( string1, format_mask )
Parameters and function arguments
- string1 – String that will be converted to a date.
- format_mask – The format that will be used to convert string1 to date. This can be one of the following and can be used in many combinations.
| Parameter | Explanation |
| YYYY | 4-digit year |
| Y,YYY | 4-digit semicolon year |
| YYY YYY | Last 3, 2 or 1 digit (and) years |
| IYYY | The 4-digit year according to ISO standard |
| IYY IYI | Last 3, 2 or 1 digit(s) of ISO year |
| Q | A quarter of the year (1, 2, 3, 4; JAN-MAR = 1) |
| ММ | Month (01-12; JAN = 01) |
| MON | Abbreviated name of a month in upper case |
| Mon | Abbreviated name of the month with a capital letter |
| mon | Abbreviated name of a month in lower case |
| MONTH | The name of the month in capital letters, completed with spaces up to 9 characters long |
| Month | The name of the month with a capital letter, supplemented with spaces up to 9 characters long |
| month | The name of the month in lowercase letters, supplemented with spaces up to 9 characters long |
| RM | One month with Roman numerals |
| rm | Month in lowercase Roman numerals |
| WW | Week of the year (1-53), where week 1 begins on the first day of the year |
| W | Week of the month (1-5), where week 1 begins on the first day of the month |
| IW | ISO Week of the year (01-53) |
| DAY | The name of the day in capital letters, completed with spaces up to 9 characters long |
| Day | The name of the day with a capital letter, completed with spaces up to 9 characters long |
| day | The name of the day in lowercase letters, completed with spaces up to 9 characters long |
| DY | Abbreviated name of the day in upper case |
| Dy | Abbreviated name of the day with a capital letter |
| dy | Abbreviated name of the day in lowercase letters |
| DDD | Day of the year (1-366) |
| IDDD | Day of the year based on ISO year |
| DD | Day of the month (01-31) |
| D | Day of the week (1-7, where 1 = Sunday, 7 = Saturday) |
| ID | Day of the week based on ISO year (1-7, where 1 = Monday, 7 = Sunday) |
| J | Julian day; the number of days from midnight November 24, 4714 BC. |
| HH | One o’clock of the day (01-12) |
| HH12 | One o’clock of the day (01-12) |
| HH24 | One o’clock of the day (00-23) |
| MI | One minute (00-59) |
| SS | One second (00-59) |
| MS | Millisecond (000-999) |
| US | Microsecond (000000-999999) |
| SSSS | Seconds after midnight (0-86399) |
| am, AM, pm, or PM | Meridian Indicator |
| a.m., A.M., p.m., or P.M. | Meridian Indicator |
| ad, AD, a.d., or A.D | AD indicator |
| bc, BC, b.c., or B.C. | BC Indicator |
| TZ | Name of the time zone in upper case |
| tz | Name of the time zone in lower case |
| CC | 2-digit century |
The to_date function can be used in future versions of PostgreSQL
PostgreSQL 11, PostgreSQL 10, PostgreSQL 9.6, PostgreSQL 9.5, PostgreSQL 9.4, PostgreSQL 9.3, PostgreSQL 9.2, PostgreSQL 9.1, PostgreSQL 9.0, PostgreSQL 8.4.
Let’s look at some examples of to_date functions to see how to_date can be used in PostgreSQL.
SELECT to_date('2019/04/23', 'YYYY/MM/DD');
-- Result: 2019-04-23
SELECT to_date('042319', 'MMDDYY');
-- Result: 2019-04-23
SELECT to_date('February 08, 2019', 'Month DD, YYYYY');
-- Result: 2019-02-08
Date functions in PostgreSQL , Time functions in PostgreSQL
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