Contents
pg_encoding_to_char()
pg_encoding_to_char() is a system function for converting an encoding's internal identifier to a human-readble name.
pg_encoding_to_char() was added in PostgreSQL 7.0.
Usage
pg_encoding_to_char (integer) →name
In system catalog relations, references to individual encodings are stored as integers, as defined in the C enum pg_enc in src/include/mb/pg_wchar.h (note there is no guarantee these values will remain stable across PostgreSQL releases). pg_encoding_to_char() can be used to convert these integer values to a human-readable format.
The following system catalog tables contain encoding references as integers:
pg_collation(columncollencoding)pg_conversion(columnsconforencodingandcontoencoding)pg_database(columnencoding)
Prior to PostgreSQL 15, this function was not referenced in the PostgreSQL documentation.
Change history
- PostgreSQL 15
- documentation added (commit f6b5d05b)
- PostgreSQL 7.0
- added (commit 5eb1d0de)
Examples
Basic usage example for pg_encoding_to_char():
postgres=# SELECT pg_encoding_to_char(1); pg_encoding_to_char --------------------- EUC_JP (1 row)
A more practical example converting the encoding column in pg_database to a human-readable value:
postgres=# SELECT datname, pg_encoding_to_char(encoding) AS encoding
FROM pg_database ORDER BY 1;
datname | encoding
-----------+----------
foo | EUC_JP
postgres | UTF8
template0 | UTF8
template1 | UTF8
(4 rows)
An empty string is returned if an invalid encoding number is provided:
postgres=# SELECT pg_encoding_to_char(-1), pg_encoding_to_char(-1) IS NULL;
pg_encoding_to_char | ?column?
---------------------+----------
| f
(1 row)