The character set support in PostgreSQL
   allows you to store text in a variety of character sets (also called
   encodings), including
   single-byte character sets such as the ISO 8859 series and
   multiple-byte character sets such as EUC (Extended Unix
   Code), UTF-8, and Mule internal code.  All supported character sets
   can be used transparently by clients, but a few are not supported
   for use within the server (that is, as a server-side encoding).
   The default character set is selected while
   initializing your PostgreSQL database
   cluster using initdb.  It can be overridden when you
   create a database, so you can have multiple
   databases each with a different character set.
  
   An important restriction, however, is that each database's character set
   must be compatible with the database's LC_CTYPE (character
   classification) and LC_COLLATE (string sort order) locale
   settings. For C or
   POSIX locale, any character set is allowed, but for other
   libc-provided locales there is only one character set that will work
   correctly.
   (On Windows, however, UTF-8 encoding can be used with any locale.)
   If you have ICU support configured, ICU-provided locales can be used
   with most but not all server-side encodings.
  
Table 24.1 shows the character sets available for use in PostgreSQL.
Table 24.1. PostgreSQL Character Sets
| Name | Description | Language | Server? | ICU? | Bytes/Char | Aliases | 
|---|---|---|---|---|---|---|
| BIG5 | Big Five | Traditional Chinese | No | No | 1–2 | WIN950,Windows950 | 
| EUC_CN | Extended UNIX Code-CN | Simplified Chinese | Yes | Yes | 1–3 | |
| EUC_JP | Extended UNIX Code-JP | Japanese | Yes | Yes | 1–3 | |
| EUC_JIS_2004 | Extended UNIX Code-JP, JIS X 0213 | Japanese | Yes | No | 1–3 | |
| EUC_KR | Extended UNIX Code-KR | Korean | Yes | Yes | 1–3 | |
| EUC_TW | Extended UNIX Code-TW | Traditional Chinese, Taiwanese | Yes | Yes | 1–4 | |
| GB18030 | National Standard | Chinese | No | No | 1–4 | |
| GBK | Extended National Standard | Simplified Chinese | No | No | 1–2 | WIN936,Windows936 | 
| ISO_8859_5 | ISO 8859-5, ECMA 113 | Latin/Cyrillic | Yes | Yes | 1 | |
| ISO_8859_6 | ISO 8859-6, ECMA 114 | Latin/Arabic | Yes | Yes | 1 | |
| ISO_8859_7 | ISO 8859-7, ECMA 118 | Latin/Greek | Yes | Yes | 1 | |
| ISO_8859_8 | ISO 8859-8, ECMA 121 | Latin/Hebrew | Yes | Yes | 1 | |
| JOHAB | JOHAB | Korean (Hangul) | No | No | 1–3 | |
| KOI8R | KOI8-R | Cyrillic (Russian) | Yes | Yes | 1 | KOI8 | 
| KOI8U | KOI8-U | Cyrillic (Ukrainian) | Yes | Yes | 1 | |
| LATIN1 | ISO 8859-1, ECMA 94 | Western European | Yes | Yes | 1 | ISO88591 | 
| LATIN2 | ISO 8859-2, ECMA 94 | Central European | Yes | Yes | 1 | ISO88592 | 
| LATIN3 | ISO 8859-3, ECMA 94 | South European | Yes | Yes | 1 | ISO88593 | 
| LATIN4 | ISO 8859-4, ECMA 94 | North European | Yes | Yes | 1 | ISO88594 | 
| LATIN5 | ISO 8859-9, ECMA 128 | Turkish | Yes | Yes | 1 | ISO88599 | 
| LATIN6 | ISO 8859-10, ECMA 144 | Nordic | Yes | Yes | 1 | ISO885910 | 
| LATIN7 | ISO 8859-13 | Baltic | Yes | Yes | 1 | ISO885913 | 
| LATIN8 | ISO 8859-14 | Celtic | Yes | Yes | 1 | ISO885914 | 
| LATIN9 | ISO 8859-15 | LATIN1 with Euro and accents | Yes | Yes | 1 | ISO885915 | 
| LATIN10 | ISO 8859-16, ASRO SR 14111 | Romanian | Yes | No | 1 | ISO885916 | 
| MULE_INTERNAL | Mule internal code | Multilingual Emacs | Yes | No | 1–4 | |
| SJIS | Shift JIS | Japanese | No | No | 1–2 | Mskanji,ShiftJIS,WIN932,Windows932 | 
| SHIFT_JIS_2004 | Shift JIS, JIS X 0213 | Japanese | No | No | 1–2 | |
| SQL_ASCII | unspecified (see text) | any | Yes | No | 1 | |
| UHC | Unified Hangul Code | Korean | No | No | 1–2 | WIN949,Windows949 | 
| UTF8 | Unicode, 8-bit | all | Yes | Yes | 1–4 | Unicode | 
| WIN866 | Windows CP866 | Cyrillic | Yes | Yes | 1 | ALT | 
| WIN874 | Windows CP874 | Thai | Yes | No | 1 | |
| WIN1250 | Windows CP1250 | Central European | Yes | Yes | 1 | |
| WIN1251 | Windows CP1251 | Cyrillic | Yes | Yes | 1 | WIN | 
| WIN1252 | Windows CP1252 | Western European | Yes | Yes | 1 | |
| WIN1253 | Windows CP1253 | Greek | Yes | Yes | 1 | |
| WIN1254 | Windows CP1254 | Turkish | Yes | Yes | 1 | |
| WIN1255 | Windows CP1255 | Hebrew | Yes | Yes | 1 | |
| WIN1256 | Windows CP1256 | Arabic | Yes | Yes | 1 | |
| WIN1257 | Windows CP1257 | Baltic | Yes | Yes | 1 | |
| WIN1258 | Windows CP1258 | Vietnamese | Yes | Yes | 1 | ABC,TCVN,TCVN5712,VSCII | 
      Not all client APIs support all the listed character sets. For example, the
      PostgreSQL
      JDBC driver does not support MULE_INTERNAL, LATIN6,
      LATIN8, and LATIN10.
     
      The SQL_ASCII setting behaves considerably differently
      from the other settings.  When the server character set is
      SQL_ASCII, the server interprets byte values 0–127
      according to the ASCII standard, while byte values 128–255 are taken
      as uninterpreted characters.  No encoding conversion will be done when
      the setting is SQL_ASCII.  Thus, this setting is not so
      much a declaration that a specific encoding is in use, as a declaration
      of ignorance about the encoding.  In most cases, if you are
      working with any non-ASCII data, it is unwise to use the
      SQL_ASCII setting because
      PostgreSQL will be unable to help you by
      converting or validating non-ASCII characters.
     
     initdb defines the default character set (encoding)
     for a PostgreSQL cluster. For example,
initdb -E EUC_JP
     sets the default character set to
     EUC_JP (Extended Unix Code for Japanese).  You
     can use --encoding instead of
     -E if you prefer longer option strings.
     If no -E or --encoding option is
     given, initdb attempts to determine the appropriate
     encoding to use based on the specified or default locale.
    
You can specify a non-default encoding at database creation time, provided that the encoding is compatible with the selected locale:
createdb -E EUC_KR -T template0 --lc-collate=ko_KR.euckr --lc-ctype=ko_KR.euckr korean
     This will create a database named korean that
     uses the character set EUC_KR, and locale ko_KR.
     Another way to accomplish this is to use this SQL command:
CREATE DATABASE korean WITH ENCODING 'EUC_KR' LC_COLLATE='ko_KR.euckr' LC_CTYPE='ko_KR.euckr' TEMPLATE=template0;
     Notice that the above commands specify copying the template0
     database.  When copying any other database, the encoding and locale
     settings cannot be changed from those of the source database, because
     that might result in corrupt data.  For more information see
     Section 23.3.
    
     The encoding for a database is stored in the system catalog
     pg_database.  You can see it by using the
     psql -l option or the
     \l command.
$ psql -l
                                         List of databases
   Name    |  Owner   | Encoding  |  Collation  |    Ctype    |          Access Privileges
-----------+----------+-----------+-------------+-------------+-------------------------------------
 clocaledb | hlinnaka | SQL_ASCII | C           | C           |
 englishdb | hlinnaka | UTF8      | en_GB.UTF8  | en_GB.UTF8  |
 japanese  | hlinnaka | UTF8      | ja_JP.UTF8  | ja_JP.UTF8  |
 korean    | hlinnaka | EUC_KR    | ko_KR.euckr | ko_KR.euckr |
 postgres  | hlinnaka | UTF8      | fi_FI.UTF8  | fi_FI.UTF8  |
 template0 | hlinnaka | UTF8      | fi_FI.UTF8  | fi_FI.UTF8  | {=c/hlinnaka,hlinnaka=CTc/hlinnaka}
 template1 | hlinnaka | UTF8      | fi_FI.UTF8  | fi_FI.UTF8  | {=c/hlinnaka,hlinnaka=CTc/hlinnaka}
(7 rows)
      On most modern operating systems, PostgreSQL
      can determine which character set is implied by the LC_CTYPE
      setting, and it will enforce that only the matching database encoding is
      used.  On older systems it is your responsibility to ensure that you use
      the encoding expected by the locale you have selected.  A mistake in
      this area is likely to lead to strange behavior of locale-dependent
      operations such as sorting.
     
      PostgreSQL will allow superusers to create
      databases with SQL_ASCII encoding even when
      LC_CTYPE is not C or POSIX.  As noted
      above, SQL_ASCII does not enforce that the data stored in
      the database has any particular encoding, and so this choice poses risks
      of locale-dependent misbehavior.  Using this combination of settings is
      deprecated and may someday be forbidden altogether.
     
PostgreSQL supports automatic character set conversion between server and client for many combinations of character sets (Section 24.3.4 shows which ones).
To enable automatic character set conversion, you have to tell PostgreSQL the character set (encoding) you would like to use in the client. There are several ways to accomplish this:
        Using the \encoding command in
        psql.
        \encoding allows you to change client
        encoding on the fly. For
        example, to change the encoding to SJIS, type:
\encoding SJIS
libpq (Section 34.11) has functions to control the client encoding.
        Using SET client_encoding TO.
        Setting the client encoding can be done with this SQL command:
SET CLIENT_ENCODING TO 'value';
        Also you can use the standard SQL syntax SET NAMES
        for this purpose:
SET NAMES 'value';
To query the current client encoding:
SHOW client_encoding;
To return to the default encoding:
RESET client_encoding;
        Using PGCLIENTENCODING. If the environment variable
        PGCLIENTENCODING is defined in the client's
        environment, that client encoding is automatically selected
        when a connection to the server is made.  (This can
        subsequently be overridden using any of the other methods
        mentioned above.)
       
       Using the configuration variable client_encoding. If the
       client_encoding variable is set, that client
       encoding is automatically selected when a connection to the
       server is made.  (This can subsequently be overridden using any
       of the other methods mentioned above.)
       
     If the conversion of a particular character is not possible
     — suppose you chose EUC_JP for the
     server and LATIN1 for the client, and some
     Japanese characters are returned that do not have a representation in
     LATIN1 — an error is reported.
    
     If the client character set is defined as SQL_ASCII,
     encoding conversion is disabled, regardless of the server's character
     set.  (However, if the server's character set is
     not SQL_ASCII, the server will still check that
     incoming data is valid for that encoding; so the net effect is as
     though the client character set were the same as the server's.)
     Just as for the server, use of SQL_ASCII is unwise
     unless you are working with all-ASCII data.
    
     PostgreSQL allows conversion between any
     two character sets for which a conversion function is listed in the
     pg_conversion
     system catalog.  PostgreSQL comes with
     some predefined conversions, as summarized in
     Table 24.2 and shown in more
     detail in Table 24.3.  You can
     create a new conversion using the SQL command
     CREATE CONVERSION.  (To be used for automatic
     client/server conversions, a conversion must be marked
     as “default” for its character set pair.)
    
Table 24.2. Built-in Client/Server Character Set Conversions
| Server Character Set | Available Client Character Sets | 
|---|---|
| BIG5 | not supported as a server encoding | 
| EUC_CN | EUC_CN, MULE_INTERNAL,UTF8 | 
| EUC_JP | EUC_JP, MULE_INTERNAL,SJIS,UTF8 | 
| EUC_JIS_2004 | EUC_JIS_2004, SHIFT_JIS_2004,UTF8 | 
| EUC_KR | EUC_KR, MULE_INTERNAL,UTF8 | 
| EUC_TW | EUC_TW, BIG5,MULE_INTERNAL,UTF8 | 
| GB18030 | not supported as a server encoding | 
| GBK | not supported as a server encoding | 
| ISO_8859_5 | ISO_8859_5, KOI8R,MULE_INTERNAL,UTF8,WIN866,WIN1251 | 
| ISO_8859_6 | ISO_8859_6, UTF8 | 
| ISO_8859_7 | ISO_8859_7, UTF8 | 
| ISO_8859_8 | ISO_8859_8, UTF8 | 
| JOHAB | not supported as a server encoding | 
| KOI8R | KOI8R, ISO_8859_5,MULE_INTERNAL,UTF8,WIN866,WIN1251 | 
| KOI8U | KOI8U, UTF8 | 
| LATIN1 | LATIN1, MULE_INTERNAL,UTF8 | 
| LATIN2 | LATIN2, MULE_INTERNAL,UTF8,WIN1250 | 
| LATIN3 | LATIN3, MULE_INTERNAL,UTF8 | 
| LATIN4 | LATIN4, MULE_INTERNAL,UTF8 | 
| LATIN5 | LATIN5, UTF8 | 
| LATIN6 | LATIN6, UTF8 | 
| LATIN7 | LATIN7, UTF8 | 
| LATIN8 | LATIN8, UTF8 | 
| LATIN9 | LATIN9, UTF8 | 
| LATIN10 | LATIN10, UTF8 | 
| MULE_INTERNAL | MULE_INTERNAL, BIG5,EUC_CN,EUC_JP,EUC_KR,EUC_TW,ISO_8859_5,KOI8R,LATIN1toLATIN4,SJIS,WIN866,WIN1250,WIN1251 | 
| SJIS | not supported as a server encoding | 
| SHIFT_JIS_2004 | not supported as a server encoding | 
| SQL_ASCII | any (no conversion will be performed) | 
| UHC | not supported as a server encoding | 
| UTF8 | all supported encodings | 
| WIN866 | WIN866, ISO_8859_5,KOI8R,MULE_INTERNAL,UTF8,WIN1251 | 
| WIN874 | WIN874, UTF8 | 
| WIN1250 | WIN1250, LATIN2,MULE_INTERNAL,UTF8 | 
| WIN1251 | WIN1251, ISO_8859_5,KOI8R,MULE_INTERNAL,UTF8,WIN866 | 
| WIN1252 | WIN1252, UTF8 | 
| WIN1253 | WIN1253, UTF8 | 
| WIN1254 | WIN1254, UTF8 | 
| WIN1255 | WIN1255, UTF8 | 
| WIN1256 | WIN1256, UTF8 | 
| WIN1257 | WIN1257, UTF8 | 
| WIN1258 | WIN1258, UTF8 | 
Table 24.3. All Built-in Character Set Conversions
| Conversion Name [a] | Source Encoding | Destination Encoding | 
|---|---|---|
| big5_to_euc_tw | BIG5 | EUC_TW | 
| big5_to_mic | BIG5 | MULE_INTERNAL | 
| big5_to_utf8 | BIG5 | UTF8 | 
| euc_cn_to_mic | EUC_CN | MULE_INTERNAL | 
| euc_cn_to_utf8 | EUC_CN | UTF8 | 
| euc_jp_to_mic | EUC_JP | MULE_INTERNAL | 
| euc_jp_to_sjis | EUC_JP | SJIS | 
| euc_jp_to_utf8 | EUC_JP | UTF8 | 
| euc_kr_to_mic | EUC_KR | MULE_INTERNAL | 
| euc_kr_to_utf8 | EUC_KR | UTF8 | 
| euc_tw_to_big5 | EUC_TW | BIG5 | 
| euc_tw_to_mic | EUC_TW | MULE_INTERNAL | 
| euc_tw_to_utf8 | EUC_TW | UTF8 | 
| gb18030_to_utf8 | GB18030 | UTF8 | 
| gbk_to_utf8 | GBK | UTF8 | 
| iso_8859_10_to_utf8 | LATIN6 | UTF8 | 
| iso_8859_13_to_utf8 | LATIN7 | UTF8 | 
| iso_8859_14_to_utf8 | LATIN8 | UTF8 | 
| iso_8859_15_to_utf8 | LATIN9 | UTF8 | 
| iso_8859_16_to_utf8 | LATIN10 | UTF8 | 
| iso_8859_1_to_mic | LATIN1 | MULE_INTERNAL | 
| iso_8859_1_to_utf8 | LATIN1 | UTF8 | 
| iso_8859_2_to_mic | LATIN2 | MULE_INTERNAL | 
| iso_8859_2_to_utf8 | LATIN2 | UTF8 | 
| iso_8859_2_to_windows_1250 | LATIN2 | WIN1250 | 
| iso_8859_3_to_mic | LATIN3 | MULE_INTERNAL | 
| iso_8859_3_to_utf8 | LATIN3 | UTF8 | 
| iso_8859_4_to_mic | LATIN4 | MULE_INTERNAL | 
| iso_8859_4_to_utf8 | LATIN4 | UTF8 | 
| iso_8859_5_to_koi8_r | ISO_8859_5 | KOI8R | 
| iso_8859_5_to_mic | ISO_8859_5 | MULE_INTERNAL | 
| iso_8859_5_to_utf8 | ISO_8859_5 | UTF8 | 
| iso_8859_5_to_windows_1251 | ISO_8859_5 | WIN1251 | 
| iso_8859_5_to_windows_866 | ISO_8859_5 | WIN866 | 
| iso_8859_6_to_utf8 | ISO_8859_6 | UTF8 | 
| iso_8859_7_to_utf8 | ISO_8859_7 | UTF8 | 
| iso_8859_8_to_utf8 | ISO_8859_8 | UTF8 | 
| iso_8859_9_to_utf8 | LATIN5 | UTF8 | 
| johab_to_utf8 | JOHAB | UTF8 | 
| koi8_r_to_iso_8859_5 | KOI8R | ISO_8859_5 | 
| koi8_r_to_mic | KOI8R | MULE_INTERNAL | 
| koi8_r_to_utf8 | KOI8R | UTF8 | 
| koi8_r_to_windows_1251 | KOI8R | WIN1251 | 
| koi8_r_to_windows_866 | KOI8R | WIN866 | 
| koi8_u_to_utf8 | KOI8U | UTF8 | 
| mic_to_big5 | MULE_INTERNAL | BIG5 | 
| mic_to_euc_cn | MULE_INTERNAL | EUC_CN | 
| mic_to_euc_jp | MULE_INTERNAL | EUC_JP | 
| mic_to_euc_kr | MULE_INTERNAL | EUC_KR | 
| mic_to_euc_tw | MULE_INTERNAL | EUC_TW | 
| mic_to_iso_8859_1 | MULE_INTERNAL | LATIN1 | 
| mic_to_iso_8859_2 | MULE_INTERNAL | LATIN2 | 
| mic_to_iso_8859_3 | MULE_INTERNAL | LATIN3 | 
| mic_to_iso_8859_4 | MULE_INTERNAL | LATIN4 | 
| mic_to_iso_8859_5 | MULE_INTERNAL | ISO_8859_5 | 
| mic_to_koi8_r | MULE_INTERNAL | KOI8R | 
| mic_to_sjis | MULE_INTERNAL | SJIS | 
| mic_to_windows_1250 | MULE_INTERNAL | WIN1250 | 
| mic_to_windows_1251 | MULE_INTERNAL | WIN1251 | 
| mic_to_windows_866 | MULE_INTERNAL | WIN866 | 
| sjis_to_euc_jp | SJIS | EUC_JP | 
| sjis_to_mic | SJIS | MULE_INTERNAL | 
| sjis_to_utf8 | SJIS | UTF8 | 
| windows_1258_to_utf8 | WIN1258 | UTF8 | 
| uhc_to_utf8 | UHC | UTF8 | 
| utf8_to_big5 | UTF8 | BIG5 | 
| utf8_to_euc_cn | UTF8 | EUC_CN | 
| utf8_to_euc_jp | UTF8 | EUC_JP | 
| utf8_to_euc_kr | UTF8 | EUC_KR | 
| utf8_to_euc_tw | UTF8 | EUC_TW | 
| utf8_to_gb18030 | UTF8 | GB18030 | 
| utf8_to_gbk | UTF8 | GBK | 
| utf8_to_iso_8859_1 | UTF8 | LATIN1 | 
| utf8_to_iso_8859_10 | UTF8 | LATIN6 | 
| utf8_to_iso_8859_13 | UTF8 | LATIN7 | 
| utf8_to_iso_8859_14 | UTF8 | LATIN8 | 
| utf8_to_iso_8859_15 | UTF8 | LATIN9 | 
| utf8_to_iso_8859_16 | UTF8 | LATIN10 | 
| utf8_to_iso_8859_2 | UTF8 | LATIN2 | 
| utf8_to_iso_8859_3 | UTF8 | LATIN3 | 
| utf8_to_iso_8859_4 | UTF8 | LATIN4 | 
| utf8_to_iso_8859_5 | UTF8 | ISO_8859_5 | 
| utf8_to_iso_8859_6 | UTF8 | ISO_8859_6 | 
| utf8_to_iso_8859_7 | UTF8 | ISO_8859_7 | 
| utf8_to_iso_8859_8 | UTF8 | ISO_8859_8 | 
| utf8_to_iso_8859_9 | UTF8 | LATIN5 | 
| utf8_to_johab | UTF8 | JOHAB | 
| utf8_to_koi8_r | UTF8 | KOI8R | 
| utf8_to_koi8_u | UTF8 | KOI8U | 
| utf8_to_sjis | UTF8 | SJIS | 
| utf8_to_windows_1258 | UTF8 | WIN1258 | 
| utf8_to_uhc | UTF8 | UHC | 
| utf8_to_windows_1250 | UTF8 | WIN1250 | 
| utf8_to_windows_1251 | UTF8 | WIN1251 | 
| utf8_to_windows_1252 | UTF8 | WIN1252 | 
| utf8_to_windows_1253 | UTF8 | WIN1253 | 
| utf8_to_windows_1254 | UTF8 | WIN1254 | 
| utf8_to_windows_1255 | UTF8 | WIN1255 | 
| utf8_to_windows_1256 | UTF8 | WIN1256 | 
| utf8_to_windows_1257 | UTF8 | WIN1257 | 
| utf8_to_windows_866 | UTF8 | WIN866 | 
| utf8_to_windows_874 | UTF8 | WIN874 | 
| windows_1250_to_iso_8859_2 | WIN1250 | LATIN2 | 
| windows_1250_to_mic | WIN1250 | MULE_INTERNAL | 
| windows_1250_to_utf8 | WIN1250 | UTF8 | 
| windows_1251_to_iso_8859_5 | WIN1251 | ISO_8859_5 | 
| windows_1251_to_koi8_r | WIN1251 | KOI8R | 
| windows_1251_to_mic | WIN1251 | MULE_INTERNAL | 
| windows_1251_to_utf8 | WIN1251 | UTF8 | 
| windows_1251_to_windows_866 | WIN1251 | WIN866 | 
| windows_1252_to_utf8 | WIN1252 | UTF8 | 
| windows_1256_to_utf8 | WIN1256 | UTF8 | 
| windows_866_to_iso_8859_5 | WIN866 | ISO_8859_5 | 
| windows_866_to_koi8_r | WIN866 | KOI8R | 
| windows_866_to_mic | WIN866 | MULE_INTERNAL | 
| windows_866_to_utf8 | WIN866 | UTF8 | 
| windows_866_to_windows_1251 | WIN866 | WIN | 
| windows_874_to_utf8 | WIN874 | UTF8 | 
| euc_jis_2004_to_utf8 | EUC_JIS_2004 | UTF8 | 
| utf8_to_euc_jis_2004 | UTF8 | EUC_JIS_2004 | 
| shift_jis_2004_to_utf8 | SHIFT_JIS_2004 | UTF8 | 
| utf8_to_shift_jis_2004 | UTF8 | SHIFT_JIS_2004 | 
| euc_jis_2004_to_shift_jis_2004 | EUC_JIS_2004 | SHIFT_JIS_2004 | 
| shift_jis_2004_to_euc_jis_2004 | SHIFT_JIS_2004 | EUC_JIS_2004 | 
| [a] 
           The conversion names follow a standard naming scheme: The
           official name of the source encoding with all
           non-alphanumeric characters replaced by underscores, followed
           by  | ||
These are good sources to start learning about various kinds of encoding systems.
         Contains detailed explanations of EUC_JP,
         EUC_CN, EUC_KR,
         EUC_TW.
        
The web site of the Unicode Consortium.
UTF-8 (8-bit UCS/Unicode Transformation Format) is defined here.